These are a few little fluffy vignettes of Phineas and Isabella's relationship, covering from their first meeting (age 8) up to going off to college, all set in the time line from 'Back in Time for Dinner'. T rated for teen romance, but these should all be tamer than Back in Time, I think; if one isn't, I'll warn at the top.

First up, we have 'First Fight'; upcoming entries include 'First Meeting', 'First Date', and 'First Christmas'. I'm open to suggestions for others. (First Kiss (that they remember) was in Back in Time, although I may include a new version of that one from Phineas's perspective.)

More adult firsts may get spun off into a separate M-rated fic, but won't appear here. Stuff after they get to college will go into a Ferbnessa fic I'm working on, tentatively titled, 'What's Up, Doc?'

And so, with no further ado: Their First Fight, set about a week after Back in Time for Dinner. Isabella's 15 here, Phineas is about a month shy of 15.

"You didn't even ask me!" Isabella shouted at Phineas.

"I'm sorry, I just worry you'd go along with whatever I want to do to keep me as your boyfriend," he answered, hoping this would help calm her down.

"Why on Earth would I think that? Phineas, I have a brain. I can be responsible for myself. I certainly never expected you to think otherwise. I'd at least like you to ask my opinion instead of just assuming I want to say no!" She evidently wasn't calming down, and neither was he.

"You never expected...let me guess, dream Phineas never did that?" He knew as soon as he'd said it it was the wrong thing to say. She'd only compared him to her idealized fantasy boyfriend twice in the week they'd been dating, but it still stung him...and now he'd stung back.

"Maybe I'm better off without either Phineas!" she shouted, slamming the gate on her way out. He called, "Wait!" but she didn't.

Phineas's shoulders slumped in defeat. With a heavy sigh, he turned to Ferb, who had busily gotten back to working on today's project - a two-person tunneling machine. That had been the problem; he hadn't wanted to assume she'd want to be involved, and hadn't wanted to ask because she'd probably say 'yes' just to be with him. But...she was right. If they were going to be dating, he needed to trust her judgement. Although being willing to date me shows her judgement is questionable in the first place, I suppose.

Isabella burst through the door of her house and ran up the stairs to her room. Throwing herself on the bed, she let the tears come out. I knew it couldn't work. It's always been him and Ferb, and sorry, Isabella, no room for a third. He didn't even ask me if I wanted to help out today.

Vivian knocked on the open door. "Isa? What's wrong?"

"I...I think I just broke up with Phineas."

Vivian sat on the bed next to her and stroked her forehead. "Oh, Isa. You think? Does he know?"

Isabella laughed, despite herself. "Yeah, I think he knows."

"What happened?"

"He just...assumed I didn't want to do something, without even asking me!" She paused and took a deep breath. The tears were fading, leaving just a feeling of wrongness. "He didn't want to ask, because...I guess he's worried that I was chasing him for so long that I might agree to anything just to keep him."

"Would you?"

"No! But when I told him that, he accused me of comparing him to my fantasy version of him!"

"Have you done that?"

"No! Well...okay, not much." She paused, then added, "Okay, not much...out loud."

Vivian gave her daughter a hug. "Can I make a suggestion?"

"Always, Mom."

"This sounds like the two of you are still figuring out the new relationship. Think about which Phineas you want to be involved with, and if it's the real one, go talk to him."

Isabella glared at her mother.

Phineas stared off into space, not seeing the open engine panel in front of him. Ferb stuck his hand in front of Phineas and waved it, causing Phineas to blink and shake his head. "Sorry, I'm just...not feeling it right now."

Ferb looked at him. I did not drop you two back in time for two days just for you to break up after a week, dammit.

"I messed up, Ferb."

Ferb continued to look at him. Okay, he's figuring it out. Hopefully the damage isn't permanent.

"I...should I go talk to her? She probably doesn't want to talk to me. I need to go try."

He was almost at the gate when it opened. Isabella stood there, concern and trepidation in her eyes.

"Whatcha doin'?" she asked hesitantly.

"I was just coming over to talk to you," Phineas said. "I'm sorry. I shouldn't have said...what I said."

"I'm sorry too. I think I'm done with fantasy Phineas...but I'd really like to keep seeing real Phineas."

"I'd like that too. I'm sorry I didn't make room for you in today's project."

Ah. My cue.

Ferb spoke up. "There's a third seat here, by the way."

Phineas and Isabella looked at him as one. Phineas spoke first. "Wait...when did you add that?"

"While you were busy moping."

Phineas smiled. "Isabella, would you care to join us for the inaugural voyage?"

Isabella smiled back. "I'd love to."