Questioning my sexuality and feeling repulsed by sex

I've had an inkling I may be asexual but I don't entirely know. I feel like I was introduced to everything too quickly and now I'm repulsed by it all. I'll kiss, cuddle, so on, but anything more than that scares me, digusts me sometimes. I would do something to someone else, sexual wise, but would prefer not having it done to me. Is it a trust thing? Am I asexual ? I think about sex and at times it appeals, others I just can't imagine doing it