Crush on a 14-Year-Old (I'm 16)?

I’m a 16-year-old girl and I have a crush on my friend (a 14-year-old girl). And this is where it gets a tad weird and graphic: I’ve started wanting to have sex with her, and I think about doing it a lot. It’s even worse because she doesn’t even know that much about sex (like, she knows what it is and what goes on but she’s still confused?) and so basically I feel creepy and like I have this huge secret burden I’m keeping from her and I don’t know if I should be thinking these thoughts or not because of the age difference (it’s mostly the sex stuff I’m worried about). I don’t know.