yeah no so basically Character A canonically in Random's story is yeah-bratty, vain, selfish, a jackass, etc. Character A in real life is literally none of those things and so when she gets transported into the story it's like "Wait is this how this person sees me cuz like I've never done-ANY of these things."
The reason WHY she's the villain in this story is that Character A is pretty, and fairly talented like she does sport-shit and stuff like that. So she's moderately well-liked in school and "Popular"...but obviously people aren't one dimensional so no, she's not a catty, slutty, condescending bitch she's just-a PERSON.