I don't really see why this has the delinquent tag unless it is for the bullies?
I think it's kinda like Futari Monologue, in which the gyaru is considered a delinquent despite being a softie, she did say she skips class and all.
Ah she does, missed that bit. That is 100% delinquency going by Japan (manga).
But this doesn't even feel like the delinquent trope where they are really nice and pure when you get to know them, she is just nice.
She also beat up a couple of people who were both larger than her. Even if they arguably deserved that, it would still take quite a bit of skill on her part and that implies she gets into fights, or at least practices fighting, fairly regularly.
She's definitely a delinquent, but that doesn't mean she's necessarily a bad person.