Last night I was with my girlfriend, we've never had sex yet together, but i've had it in previous relationships and she's a virgin. we got on the subject of doing it and i asked her if she had wanted to, and she told me she didn't know - she wasn't sure if she had wanted to that night or not, but she had kept thinking about it. about a half hour to an hour later, we were laying there, talking and such, and i could tell she was still thinking about it so i had told her to stop that we didn't have to that night. so, about a half hour later she says she wants to, i'm just tired because i had worked one to nine and then went straight to her place and it was about 2:45AM by now - usually i can't keep my eyes open any longer and just leave at 3. She says she wants to and i am all for it, so i go down on her just to help her loosen up a little more, and at this time, im trying to get a hard on and it's not just working. from about 10-2AM i had a raging hard on as she was on top of me and as we were making out, but now that i finally needed it and could put it to use, i couldn't get one if my life depended on it. maybe it was just nerves? i mean, i wasn't nervous at all, but the fact that she had put so much thought into it before hand and that i told her we didn't have to i think made it hard for me to get one. any advice or suggestions of what happened?