Sorry, honey...I don't love you

I feel kind of guilty.
There's this girl who I know has had a crush on me probably since third grade. Well, I'm in eleventh grade now, and so is she. That's eight years. That's a long time to be in love with someone. If she's loved for that long, she probably would be a very good girlfriend. There's a problem, though. I like boys.
I hope she finds someone new. I'd love to be her friend, she's really nice, but I feel that if I offer friendship, she'll try to "turn" me. Sorry, honey, I am what I am.
I just had to get that out. I could use some advice.