I’m tired of this relationship

So I’ve been together with my gf for some time, and it’s been fine. She’s enjoyable to be around, but I would say I’m in love. We are both 15, so if anything here seems childish that’s why.

First I’ll give you some background information. Originally she asked me out, and I said yes. This just happened to be after my classmates figured out I had smoked weed. I don’t know if those two correlate. In the beginning she was nice and pretty reserved. Lately she’s beginning to feel like a different person, she cuts herself, she drinks (more than normal people our age do) and she wants to smoke weed. Something I quite a while ago. Nowadays I only smoke some sugars every once in a while to satisfy oral cravings (I’m in the process of stopping).

One thing that made me rethink our relationship was a discussion in alcohol. I don’t drink, because I don’t really like being intoxicated. I asked her why she drinks, and she said it’s to drink away her problems. There just seemed to be something off about how she said it, like she seemed to want validation.

Our main issue is that she wants to have sex, which is something I do not want to. We haven’t even kissed yet. The reason I have reservations about doing this stuff, is the fact that I don’t know what her motives are. She only seems to want to have sex to get bragging points among the other girls. I do not feel comfortable loosing my virginity to someone who only does it because of social pressure. She seems to care way too much about everyone else. I don’t know what I’m to do.

I like her, but I don’t like the pressure put on me.

TLDR: my gf is obsessed whit social validation, and I’m tired of it