[Xirokz]

Short: I cant keep it up long enough to have sex, i think its because of performance anxiety what should i do about it ?

LONG:
I have been having a problem staying erect enough to have intercourse. What do you guys think would be the best thing for me to do so I can finally get this virginity thing out of the way. I am 19 and she is one year younger, have been dating for over 3 months and I feel like this relationship is going to last. We are both virgins but have had some intimate experience with our previous partners. I feel very comfortable around her at all times, all except when we are both naked and this problem fucks things up again.
The problem: Me and my girlfriend have tried to have sex 3 times, but I have never been able to get it in because my erection is not hard enough or none existing.
I don't think I have a real physical Erectile Dysfunction because I can get very hard and sustain the erection during masturbation. I get an erection every time we are making out passionately and if she has to go after like 20minutes and I'm readjusting myself down there it seems rocksolid.
Unfortunately my girlfriend is almost always under time pressure and she will often just meet me for an hour or less and because i have gotten used to this I normally don't make any moves that would indicate that i want to advance to sex. All of those 3 times during which i failed to stay up, we had been making out for something like 30-45 if not more and then she would say something like, "I think I'm gonna stay until 10:30"(after having previously stated that she needed to be somewhere at 9:45) or she'll say something like "I think i can stay another half an hour". Once i get the message, that she wants to have sex I turn the making out into more energetic foreplay and we take our clothes off. Normally I will start by trying to please her first just because I don't want to just jump right in because I am thinking about her more than me. And once its time for actual penetration my penis just is not hard enough.
Since it was now the 3rd time this happened it was thinking about getting it up, which i heard was bad enough of a distraction from the act that it can cause you to go limp. Also I am constantly concerned with weather or not what i am doing is what she wants. I have pretty bad performance anxiety with anything that has to do with her, maybe just because I am madly in love and want to do everything right or maybe because I just want to be the perfect boyfriend, I'm not sure.
An additional complication is what she does in bed, nothing. We are both virgins but have had experience with other partners just nothing that actually lead to sex. When we are making out her favorite spot is just on my bed under covers and with her on the bottom, every time. She wants it but she does not do anything to she me that she does. The first time she spent the night I stopped before intercourse with both of us naked, I thought she was not moving because she was just really stoned or something and i was taking advantage of her. But almost nothing has changed a month and a half later, she still wants me on top and just lets me do everything. Not complaining but also not asking for anything. I'v talked to her about this and she realizes that i think its a problem but it still has not changed. I'm not trying to blame my inability to sustain my erection on her but i think that is part of the problem. Last night (the 3rd incident) we got to the same point: We had been making out for half an hour then she tells me o i think i can stay for another hour and i start taking her cloths off again and trying to make her come while trying to get hard again. This last time i asked her to get on top and i just asked her to help me (with which i just ment maybe move around a bit or touch my chest IDK what ever women do before sex) but she did know what to do and was just laying on top of me. Then i try to ask her to get more involved but the only thing she can come up with is to give me handjob and then a blowjob which just made me lose my erection completely. This is the point where I'm not sure if it really is just psychological because she had it in her mouth, how can that not get me up. After she noticed that the blowjob was not helping anything it all ended. After which you can imagine i was pretty angry with myself. And the thought of me not being able to have sex with this extremely attractive girl that i am in love with kept me up all night. Literally i was up for 7 hours watching my ceiling fan.