Have a feeling the problem may solve itself. Chances are, someone's going to white knight and tell her. Not me though...
That being said, relationships are tricky. She's young, and so probably still sees anyone who has so much as grazed her vagina with the back of their hand as a boyfriend. Honesty is going to be key, here. Tell her that it's all moving a bit fast for you, and you want to take things slow so that you don't freak out and get commitment-phobic. Give it time, get to know her (more than just her pussy), and see if you guys click. You might end up wanting more. Same thing happened to me, and I ended up marrying her. Aside from the cosplaying part.
