So, i am a 19 year old male. I am currently a virgin. So me and this girl im talking to for a few months we decided to finaly have Sex. It was going great untill it actually got into the sex part. Well im turned on the whole time, until im on top of her naked and are about to insert. Basicly seconds before we are about to do it my erection just goes away. Dont know why. Maybe is because is my first time and im nervous but i need help with this. Im afraid it can get worst.