I'm a bit disappointed with the whole "delinquent" thing, because it's shown that she was never mean-spirited, which makes the whole redemption shallow. There really is nothing to forgive. Even with the one person she "hurt" (while they were ganging up on someone 5v1), they're probably going to reveal that she didn't actually punch his tooth out and it was all a front he put up to justify dropping out of the team for some other reason. In the end, being a "delinquent" is just "being different and unpopular". When the popular guys are meand and violent, that's not delinquency apparently. Kotoko refused to dress like a stereotypical girl and stood up to others to protect unpopular guys? Unforgivable delinquent.
I guess for a repressive culture standing out is a bigger crime than actually being evil. But for a western audience, the whole conflict falls flat because Kotoko had the appearance of a bully, but never actually hurt anyone who didn't deserve it. Ako is a psychotic criminal who has commited multiple actual crimes (blackmail, attempted to cause serious injuries, defamation, harrassment, and so on) and abused not just her target but other people who's only "crime" was feeling indebted to her. But she doesn't wear a popped collar, so she's not a delinquent and no one really calls her out on her bullshit.