Has anyone ever realized that their a terrible person who doesn't treat people properly? Can you change?

I just had an epiphany when i was on a 8 hour bus ride and had nothing to do. I realized that i have always been a very superficial person who is always belittling people, very selfish, doesn't care about other people, doesn't like spending money on other people, uses people only interested in going out partying and picking up girls, and being condescending saying mean stuff about people being inappropriate making girls cry, and the worst part thinking that I'm better than people when I have so many problems myself. I just realized that and I feel so bad about my self is it hard to change i'm 19 and going to university next year. The worst part is I used to think i was a good guy and that I was always nice to people but i realize now that I'm inherently a mean person.