I had this at the age of 16 with my first boyfriend, they were madly in love with each other. When it came to intimacy, me and him, it's so exciting. Just try to relax and enjoy what is happening.
If you like each other and plan to meet, then you need to use some kind of FETISH. For example girls have a drink with a sober guy. Really drink champagne. Maybe become unnecessarily untied, start complaining that she is not loved. Behave very freely. Before that, find out the guy's sexual preferences. To do everything for her is natural and sexy, as it were, by the way. Maybe the guy's reaction will be positive.
I can tell my story. I did it the first time from the fourth time. Everything was fine, but every time at half past six in the middle of the process. My girlfriend figured it out. At the moment when I began to pester her once again, she began to pretend inaccessibility and did not want to give herself up at all. It was then that I caught fire. Since then, no problems in this regard.
I had a similar experience at the first sex. The fact is that his emotional stress suppresses sexual desire. He needs to take the accent off his penis. To do this, he needs to tell you that his penis will not get up, but he really wants intimacy (that is, he should not be soaring whether he will succeed or not). Further, he should please you in another way (cunnilingus, fisting). During this, he himself will not notice how everything will turn out)
Another way is to apply oral sex to him. Try to please him until he eats, thereby removing the restrictions from him and the next time the sexual intercourse starts with a blowjob.
If this does not help, then you need to go to intimacy gradually. He needs to get used to you. Try to sleep completely naked for a week and touch each other with your genitals as often as possible. Everything will work out within a week.
If all of the above did not help, then you should contact a psychotherapist.
Probably the guy is not ready mentally for sexual relations. Prepare together, discuss and talk about similar topics more often, treat both with humor (less seriousness, it is important at some point, but the person automatically realizes what and how in what situations). Do not forget that more or less everyone has complexes about their appearance and body in general. Try what I call "examining" each other's bodies and talking at the same time, a small amount of alcohol will defuse the atmosphere, and candles and music will improve the atmosphere in the room. Have fun with each other. When both people are free to realize that they can enjoy themselves and get off the line, the problem disappears by itself. With love, Vanya