🙁Why am I so different?🙁

I am 15 years old and I can’t help but notice I seem to be very different than the others in my year group. I mean in a way that while everyone is going out to parties and having sex with randomers, I’d rather stay at home with my parents and watch tv. I also told my friend I don’t want to have sex until I’m older and in a serious relationship and she looked at me like I was crazy. I talk differently to everyone else (they all speak very ‘chavvy’) whereas I talk quite formally compared to them. It annoys me because I always get left out of things and not included because I don’t act like the others do and do not want to do the same things like ‘tramping’ out in the streets. What should I do? Should I try change or should I just go through high school being the same boring, dependable person?😕 please help, idk I just feel really alone rn.