Im still a kid. Screw chronological and biological ages. You are whatever you feel like you are. Given the current context.
Obviously this isn't covering Neko grampa's trying to be 5 year olds or w/e. Beyond 20 it really doesn't matter though. I mean think of how stupid it is that people get looked at funny for dating with age gaps. There are reasons things don't work out sure, but people are not judging based on those which are none of their business anyway. Just like people saying "cartoons are for kids" or telling people who play video games to grow up. The way they use age is a giant pile of bullshit only reinforced by the idiocy they were raised with.