I really wish I could help you with this but I’ve had some horrible experience with sex, so please don’t take my “advice” as law, okay? I would suggest missionary or you on top of him so that you can control the speed of the penetration. Both of these positions allow you to make eye contact with your partner which I think would make it more special. As far as the pain goes using a lubricant can help reduce the amount of pain you will experience. When intercourse begins stop for a moment, with him inside you, and let yourself adjust before he fully enters.
There will be some awkwardness as you and your partner try to find a comfortable position and good rhythm but arousal helps calm those insecure moments, so have lots of foreplay.
I don’t know if any of this helps but my inbox is always open. I wish you well <3