You hate when people say “he’s mean because he has a crush on you”. It’s just a way for people to bully others with no consequences. Unfortunately it happened to you. Katsuki had bullied you worse than he had izuku. It was like that for years until you went to UA and over heard one of Katsukis conversations with kirishima where he told kirishima that her loathes you. That stung but you figured that he probably felt that way. Then the unexpected happened, he asked to be your boyfriend and you weren’t sure if you were being messed with or if he’s genuine.