Honestly, I think you should try therapy if that's an option for you. This is a very personal internal issue that I don't think this sub is fit to answer. It sounds like it's not necessarily about the relationship, but how you're processing things. All we can do is guess, but I think you would really benefit from a deeper examination of your feelings around physical intimacy than anyone here can provide. I'm not saying that there's anything wrong with you or trying to diagnose you at all. This doesn't sound very outside the realm of normal, especially for someone young and inexperienced, but it's obviously something that bothers you, and it might not just go away on its own. A therapist can help far more than a reddit thread. But that's not an option for everyone, so I hope you can figure this out one way or another.