Why dont I care what people think about me but I used to?

I remember in high school when I used to worry about what others thought about me, like me having to have the perfect boyfriend and having to win prom queen or it would be the end of the world, but now that I have been in university and have lived on my own and done whatever the hell I wanted for the past year, I just stopped caring what people think, like I honestly dont give a fck at all, I dress how I want to, date who I want and I stopped going to stupid football games which I've always secretly hated and stopped pretending to like mainstream music that my friends do. What happened to me? I kind of became a different person, my old friends from high school who cared about clothes and gossiping are completely different from my new, when I go home they can barely, metaphorically speaking, recognize me. What is going on with me, can one year really make me that different of a person? a person who just could care less what people think?