I'm not sure if this counts as a first date, but my partner and I had sex the night we first met. Call me what you will, but as someone else has said, sometimes you just click. We played safe and he spent the night at my place. That was almost 16 years ago and we are still together. I think it's one of those "to each his own" type of things. As long as you're both comfortable with it, I say go for it.