It depends, is that guy/girl someone you know. I mean was it like you were friends for a while and then went out and it happened or what? It depends on how you look at it.
probably not because if they will sleep with you on the first date, they would probably sleep with anyonw.. but like poeticpimpin123 said, it also depends alot how well you know the person in the first place
That isn't always true, though. I mean I actually lost my virginity to a girl I had known for SEVEN HOURS! It was the first date, barely even a real date, we just met at a party she invited me to (I had spoken with her online and on the phone for only a few days, i.e. I barely knew her). Things just got weird and... well, I try not to regret anything I do. In fact I rarely have regretted anything I've ever done, because not only am I calculating and efficient in my goals, but what happens that isn't part of my plan usually strengthens me in the end anyway. In this case, I do regret the situation, I should have exercised better self control. Then again, I was 21, and that's old to be a virgin, and there was some alcohol involved. We went on to have a 2-month relationship or so. She was my first serious girlfriend. I would never let that happen again, the whole first date thing, and I've only ever had sex with her, so it's not like I'm a man-whore. It was just a weird one time situation...
Well, I had sex with a girl before we ever had a first date and we were together for 5 years. I think she only loved me for my tongue.
depends on the person a lot, and what they think of you for hopping into bed with them after the first date. Personally, I don't think it would prevent me from dating someone - their personality has a lot more impact for a real relationship than their bedskills do.