No, I don't think you're being blatantly sexist, since your ideas are rooted in (i) your experiences with men, and/or (ii) social trends. That's ok. I'd never kissed anyone before I met my second boyfriend when I was 19 (he'd been in three relationships, and had a LOT more experience than I did). It wasn't an issue for us actually -- we never had sex, but he was very patient and caring, waited while I figured out kissing, etc. Yes, I agree that some men -- and even some women -- might not be ok about having an inexperienced partner. However, I really do think that people who are worth your time won't care, and the "sex" will be secondary to genuine intimacy (of course, sex can be an expression of genuine intimacy. I think you get what I mean).