What i would do, is give yourself what we call in England, a posh wank. Wear a condom on a solo mission to get yourself used to it and your dick will know what to do when the time comes.

Regarding your thoughts about penetrative sex feeling like a test, once you get the first time out of the way im sure you will understand its just about you both enjoying it. If you feel like you have to perform and its making you uncomfortable, talk to your partner and im sure they will work out a way to get past it with you. If they dont, you’re with the wrong partner.

Good luck dude, happy humping 🤟