I'd have to say it's not that big a deal over when you lose it; it's who you lose it to that matters.
I'm 18, and still a virgin. Up until I was 16, I was in a big rush to 'lose it'. (So much so, that after watching American Pie, me and my mates made a virginity pact - we'd all 'lose it' by the time our ball rolls around [july 08 sometime]). But now, I'm just not in so much of a rush.
I'd say, take a step back, and look at the pros and cons of it. To have a one night stand just because a guy thinks of you differently is absolutely pointless. As for the guy, he seems like a right idiot to think of you differently just because you're a virgin. (Believe me, I know the type. I once dated a girl who was 'more experienced' than me, and would have nothing to do with me for like a week while she thought things through). The only pro is said guy will treat you the way you like.
My group of mates are, for the most part, virgins. (Just my best mate, and an old friend from infants school aren't). We do have the odd guy who is 'dying' to lose it, and probably would have a one-nighter just to do that, but, the consensus seems to be to lose it to someone special.
Don't just lose it because you're being pressured into it. Lose it because you want to, but make it someone special, so you'll be happy about it in the end.