Why don't I want to have a ual relatiponship?

I'm 15 and have never had a boyfriend. I'm talking to this guy at the moment and I think he likes me, but whenever I think about so much as kissing him I feel repulsed! He's not ugly or anything, in fact he's just the sort of guy I would go for, its just doing anything ual makes me feel nervous and disgusted... is this normal?