Armin got a drink of water from a lazy stream flowing through a forest. It was as safe as it ever really got, when he looked in the water he was surprised that the older face belonged to him. He never really paused to look at himself, still had the shaggy blonde hair, but something was off. He quickly mounted his horse and wondered what was missing. It hadn't happened overnight, but slow enough that he hadn't noticed until then.
He was still Armin Alert, he still was in the Scout Corps, and still stuck behind the stupid walls that were almost a placebo to the rest of the human race against the Titans. The more he thought about the supposed safety of the walls, he sighed, was there any real safety? Would mankind always hide behind walls, and hunt the prey that hunted them?
He kept on fighting even though the Titans always seemed to win. The human race was dwindling and the Titans always regenerated or more appeared. Annie didn't, because she was stuck in the crystal. Would he ever see Annie again? She deserved more than that, even if the voice in the back of his head whispered she had some peace to know she couldn't hurt anyone inside the crystal. He still talked to her even though she can't hear him, because on the off chance she could there was a lot to catch her up on. He really couldn't talk to anyone else, anyway.
Armin rode on still thinking about what was missing when he finally laid his finger on it, he had somehow grown older and he was missing his innocence. The few years seemed like so much more, always scrounging for food until the Scout Corps. Constant fighting and near death experiences hadn't done him any favors. Oh, and shifting into a huge man-eating Titan. He wasn't the same person that got picked on for believing the Titans would one day attack, or relied on Mikasa and Eren to help him out of fights. At this point in his life, he wondered if could be considered a decent person. Probably not, a means to an end, at least.
When he was younger he always thought he'd grow up and do good things for people, before the Titans came he never seriously considered the Survey Corps. He never considered as a child that joining the Survey Corps he was surrounded by friends that were slowly claimed by deaths cold clutches. Nothing was the same, and he didn't think it was ever going to go back to the way it was for better or more likely, for worse.