I've ruined 3 nights so far, the first two left but the third girl is willing to try again. All because I can't get an erection. I'm not even 20y/o! This is getting to me and I have no idea what to do. I have a great testosterone level, but I just don't get that turned on when I'm with a girl. The first time it happened I stopped watching porn immediately, its been just under two months now. Should I take viagra next time? I think I would just build a mental dependency by doing so. I really need advice, being in high school, this is embarrassing to no end.

Update: thanks guys, reading and just thinking this through has really been beneficial to my state of mind