I'm not sure what to do with my girlfriend

Basically we've been together for 8 months and i'm not sure at all if I feel the same as I did when we first went out. It was amazing at first, but I started to lose interest. She wants to have sex and i'm not sure if I want to as I don't know if I love her anymore. I do feel like ending it, but at the same time I don't want to as I know it'll hurt her so much because she keeps promising we'll be together forever etc. There is a problem with her saying that. We're both only 15. We're 15 and she keeps making these big promises and I don't know if I'm ready to commit because i'm not sure if I love her anymore. Please help me.

Don't feel pressured by her... if you're not sure whether you love her or not, then don't you think that you should go with your gut instinct and hang fire? You are still a pretty young guy to think about tying yourself down, and think about the consequences if she were to get pregnant... your life could be changed forever, and you might not get to do all the things you want to if you have to look after a child. Also, 8 months together isn't at all that long you know. If she really loves you, then she will wait until you are ready to make the next move. If she was a lot older and wanted you to settle down, then this could be understandable. Let us know what decision you make, or what she says when you discuss these things with her.