Author's Note: I'm messing up the timeline of The First Avenger in this story, but I think it makes sense. It doesn't matter too much in the long run for the rest of the story, besides when it deals with Steve's age.

Tony gave Steve the rest of the day to cool off, before deciding that he'd waited long enough. They were both adults, hopefully, and they could talk this through and work things out. His evening with the other man had shown him that he actually enjoyed the super soldier's company, which was pretty surprising. Tony would've said before that they had nothing in common, but that wasn't really true. They were just normal guys. Mostly.

Jarvis had easily found Steve's address, which ended up being a basic apartment in Brooklyn. Tony hadn't been surprised at all. The man could've gotten something nice in Manhattan, but he chose something humble and out of the way.

Tony was on his way there with the perfect excuse, in case he needed one. In Steve's rush to escape his questioning, he'd left his sketchbook behind. Tony could've had it sent by carrier or waited until Steve came back to retrieve it, but this way forced the interaction. He'd peeked at the last drawing before he left, marveling at the way Steve captured the view from his tower. Anyone who put so much love into what they did was worth knowing in Tony's opinion. Too many people took no pride in their jobs or even hobbies, but Steve's passion shined through.

The building looked just as Tony imagined it would. Simple brick without any flash. Tony liked sleek metals and clean lines, but he could understand the appeal of this too. He had a few rustic cabins sprinkled around the planet to fulfill that sort of desire when it popped up.

As he trudged up the stairs to Steve's floor, Tony couldn't help wondering why he was even doing this. Why was this the thing he was pushing about? Was it his inability to ignore a mystery once it piqued his interest? Was it him being a nosy asshole? It was probably a bit of both, but he knew he had to find out the truth either way.

He knocked on the door as soon as he found the right unit, not wanting to give himself the chance to talk himself out of this. And Tony wasn't sure how sensitive Steve's super hearing was, so he didn't want to be caught sniffing around outside his door. That would be awkward and starting this talk off on the wrong foot. He needed all the good feet he could get.

"Can I help- oh. Hello Stark," Steve said as he opened the door. He didn't look mad, just a bit wary.

"Hey Rogers," Tony greeted, tipping his head politely. "May I come in?"

"I'm kind of in the middle of something," Steve sighed, blocking the small opening into the room with his body.

"I swear it won't take long." He couldn't just hand over the book now, since that was the only excuse he had to be over. And it would be harder for Steve to push him out if he actually made his way inside. He put on his best puppy dog eyes. Pepper always told him they didn't work, right before doing whatever thing he'd asked of her. And if he could sway the powerhouse that is Pepper, Captain Polite stood no chance.

"Fine, come in," Steve mumbled, stepping back and letting Tony into his apartment. The apartment full of boxes.

"What the- are you leaving?" Tony blurted out, looking around the space in dismay. Had he not only pushed Steve out of his tower, but out of the whole city?

"Kind of. It's complicated," Steve shrugged. "This place was really only temporary."

"If this is because of me-"

"It's not. It has nothing to do with you," Steve assured him, moving a couple of boxes off a couch to give them a place to sit. "Word finally came down from Shield."

"And what was the verdict?" Tony asked, even though he could pretty much guess.

"They are sending me out on a mission tomorrow. I'm taking all my stuff to Shield, since I won't need the apartment anymore."

"Why not? Why wouldn't you need a home base?" Tony questioned.

"I don't anticipate a lot of downtime between missions, so I'll just be staying in whatever Shield base they put me in. It's more efficient than having to figure out a way back and forth from here, just so I can sleep in my own place for a night," Steve shrugged. As if it was no big deal that he wasn't going to have a home anymore.

"That- that's insane! So you're just never going to get a day off?" Tony exclaimed. They were treating him like a machine, not a human being.

"It's what I signed up for."

"That's bullshit! You're still a person, not a tool to be used whenever they see fit!" Tony hissed. He had half a mind to march down there and give Fury a piece of his mind, even if he wasn't the one calling the shots. They needed to know that this wasn't right, even if Steve was unwilling to say it.

"I'm all they've got Tony."

"That's not true. They got along without you before just fine. That's just the line of crap they are feeding you now."

"Things have changed now. There are things out there that the average agent can't deal with."

"That's exactly what I'd expect them to say," Tony spat.

"I don't know what you're expecting from me, Tony. This is what I signed up for. This is what I agreed to."

"You signed up for having no personal life? Nothing to call your own?"

"Look around you, Tony. That's how I'm already living," Steve pointed out, waving a hand around his empty apartment. "Last night was basically the only time I ever did something for myself since I got here."

"And I ruined it," Tony muttered, disgusted with himself. What could've been Steve's only chance to relax had been soured by his aggressive questioning.

"You didn't ruin anything. I was just caught off-guard. No one has ever asked me questions about that, so I didn't know how to react. I'm sorry," Steve murmured. Tony's brain was screaming at him to leave it at that, but his heart was pushing him to ask more questions. If this was the last time he'd see Steve in who knows how long, the mystery would drive him crazy.

"About that…" Tony trailed off, glancing at Steve hesitantly.

"Tony."

"You can tell me. I swear I won't say anything to anybody and nothing will change," Tony insisted.

"You're already looking at me differently."

"Because the mystery is driving me insane! I at least need to know if I committed a crime by offering you alcohol last night." When Steve looked away and didn't say anything, Tony choked on his breath. "Holy shit!"

"See!"

"I'm sorry! I meant to say holey shirt, because I thought you had a hole in your shirt. It was just a shadow though, no worries."

"Right."

"Really though. It'll stay between you and me. Who would I tell?" Tony asked, raising his eyebrows innocently.

"You talk to the press all the time," Steve reminded him.

"Only about myself." Steve pursed his lips and stared down at his lap for a few moments. Tony tapped Steve's foot with his own in a show of support. "You can talk to me."

"It's a long story. Only one other person knew all of it, but he isn't here anymore," Steve whispered, clearing his throat toward the end. "Do you promise you won't say anything? I'm not sure what would happen if this got out."

"Of course. My lips are sealed," Tony assured him, mimicking locking his lips together and throwing away the key.

"I'm sure you've heard the stories of how I was really sick growing up. They were mostly true, except for a few of the stranger things I've heard. I didn't actually sleep in an iron lung every night," Steve said, shaking his head at the end. Tony had heard something about Steve having a long lost conjoined twin who was being raised to take over the world, but he figured this wasn't the time to bring it up. "The point is, I had to stay home a lot. And since we didn't have much money, I spent most of my time reading whatever books I could get my hands on from my school."

"Are you a genius too? Have you been holding out on me?" Tony teased.

"I wouldn't go that far," Steve scoffed, smiling ruefully. "But it did mean that I advanced a lot faster than my classmates. So I ended up skipping a few grades."

"Well, there's something we have in common."

"I bet our experiences differed though. I had already been the smallest one in all of my classes, but now the difference was even more jarring. It was kind of bad for a while, until I met my pal Bucky," Steve said, getting a little smile on his face. "He stood up to all the bullies and we became fast friends. Bucky didn't care that I couldn't do what all the other boys did. He liked me for me. And we were inseparable."

"That sounds familiar as well," Tony grinned, thinking of Rhodey. He never needed protecting, but Rhodey never judged him for who he was.

"I ended up graduating early, with Bucky's class. We even took a few courses at the local art school. It was going great, until my mom got sick," Steve murmured, wringing his hands in his lap. "She- um, she died."

"Oh, Steve. I'm sorry," Tony said sincerely. He knew how that felt. "How old were you?"

"Fifteen," Steve whispered, turning his head as he brushed a hand under his eyes. "I still miss her, you know? It hasn't been as long for me as it's been for everyone else."

"I get it," Tony nodded. It had been decades for him, but sometimes the ache would hit him so sharply that it stole his breath away.

"I'm sorry. I don't mean to bring up painful things for you."

"No. Say what you need and don't worry about me," Tony waved off. He'd asked for this, so he was going to sit and listen to whatever it was that Steve had to say.

"I lived with Bucky at first. The people where my mom worked knew about me, so there was a bit of talk about me going to an orphanage. Most kids my age would've been able to go off on their own, but my medical issues made them take notice. With Bucky there to help watch over me, it was okay. Until the war," Steve sighed, shaking his head. "Bucky enlisted and I wasn't even able to try, since I was too young. Everything started happening so fast, with him being sent off for training and me doing everything I could to keep our apartment and stay off the radar. But it could only work for so long."

"Sounds like a lot of responsibility for a kid," Tony mumbled, already doing the math in his head. He didn't like where he was ending up.

"I hadn't felt like a kid for so long. And having things that were out of my control determining my life was unacceptable. I couldn't let my age or my health stop me from making a difference. I didn't have the right to sit at home and do nothing while other men and women were laying down their lives for the cause. So I had to change things."

"And you decided to change your birth year by like, a decade?" Tony asked incredulously.

"It wasn't that much. And it's obvious when people lie and say they are the exact age they need to be. You have to give a bit of a buffer," Steve excused. "It didn't matter though, because I still got rejected. My health was the bigger barrier."

"How did you convince people you weren't still a teenager?"

"I just excused how young I looked on my medical issues. People didn't really care. But then I met Dr. Erskine and for some reason, he saw something in me. I agreed to whatever he wanted, because I knew that would be my only chance."

"Did he know how old you were?" Tony asked. He blew out an exasperated breath when Steve shook his head. How had no one but him seen this? "You could've been killed."

"That's a risk everyone understands and accepts when they join the Army. I was no different," Steve shrugged. "I'm sure you know the rest of the story."

"Who doesn't? You got the serum and turned into this," Tony replied, gesturing to the man's giant body.

"An added benefit was it making me look older than I was. No one had questioned me before, but now I didn't even worry about it. And I don't think anyone from home made the connection that it was me."

"So, how old were you when you got the serum? How old were you when you became Captain America?" Tony asked, ready to hear the answer. He'd gotten the story and heard the justifications, but he needed the number.

"Sixteen," Steve said softly. Tony could feel his heart clenching at the thought of this kid who'd signed his life away in an act of desperation. It had worked out for the most part, depending on how you looked at it, but it was a choice no kid should've had to make.

"And that makes you…"

"I'm nineteen now. But I'll be twenty soon," Steve tacked on quickly, as if that made a difference. A nineteen year old had just led them into battle against aliens without batting an eye.

"I'm not quite sure what to say. And that's not usually a thing I experience," Tony muttered, running a hand down his face. He was sitting next to a teenager. Steve was young enough to be his son.

"It's not that big of a deal, I don't think. It hasn't affected how I do anything. And I'm legally an adult now."

"Barely," Tony scoffed.

"Nice. Well, I need to get back to what I was doing. I'll see you around," Steve said pointedly, standing up from the couch.

"I'm sorry," Tony groaned, looking up at Steve in regret. "It's just a lot to take in."

"At least it's nothing you have to worry about anymore. It's not like we'll be working together again," Steve shrugged. "No more taking orders from a kid."

"That's not- I don't care about that. At least not how you think," Tony sighed, standing up as well. "Your life shouldn't have to be like this. You could be going to that art school or just doing whatever you want. A decision you made at sixteen years old shouldn't dictate the rest of your life." Steve looked surprised by how much he seemed to care about this. But Tony knew all about the effects of throwing so much responsibility on someone too young to deal with it. At least Tony hadn't been thrust into war.

"It's okay. This is what I chose. This is where I need to be."

"But what about what you want?" Tony challenged. Steve looked away and Tony knew that he wasn't going to be changing his mind. Steve was too stubborn to realize that he had the right to choose and put himself first, no matter what. Tony pulled the sketchbook out of his bag and held it out for Steve to take, holding onto it for a couple extra seconds as Steve tried to pull it away. "Don't let them take this away from you too."

Steve stared down at the book in his arms, running his fingers along the spine. Tony could see the longing in his eyes, even if he didn't want to admit it. His sense of responsibility to everyone but himself was still too strong.

Tony took one last look around the apartment before walking out. He knew if he stayed, he would say something he regretted. Like Steve was still too young to be going off on missions alone. But he'd promised he wouldn't say anything and nothing would change. Although, there were always ways to get around stuff like that. Tony didn't get to where he was in life without being able to bend the rules a little. Now he just needed to figure out a way to use his gift to help Steve.