It's normal to feel a bit... deflated or think "THAT was all the fuss?"
Like with all other things, it takes practice to get good. And I don't mean only managing the physical mechanics of sex but managing the emotions of sex.
So much attention is placed on "losing virginity" and "orgasm" in media, books, movies, friend's crazy stories... not a whole lot is mentioned about the "Now what?" so people are prepared for the slight deflated thing after the first time.
Not a whole lot about the interim time either. The "Ok, first time over. Now we're hunting the fireworks. Not finding them...What do we do in the meantime?"
While I hope things work out for you two, even older people go back to square one if they are in subsequent relationships and can feel a bit blah.
I was totally ready for sex, and I was prepared for the blah. It took then BF/now DH and I at least year to find out where the fireworks were for us and develop our bedroom manners.
Towards the end of that period, a friend of mine was thinking about breaking up with her BF because he wasn't a fireworks guy like a previous BF and I pointed out that she'd only been with new BF for a little bit and she'd been with the old one a while. It takes time to "learn" a new lover. She'd simply forgotten how it feels to be in the blah place and intead of thinking "Oh, it's just the normal blah space" she was thinking "Man, I must not love him any more" and was freaking out. She calmed down, remembered the blah phase, and later married him. I assume they found their fireworks in the end.
Try to not stress too much about it. I think it's a normal stage. You both need a little space and time to process it. To me it sounds like he was worrying about performance anxiety or something with the first time so he feels like that part of it has lifted for him.
I remember it was like the Weather Channel with constant updates when we were that age and first became lovers and trying to figure each other out. "That's good... no, not keen on that. How's this working for you? Wait... hang on. I feel hot/cold/thirsty...YOW! that was some COLD lube! I'm sleepy now... can we raincheck?"
We don't have that sort of talk any more because we've moved past that stage already.
But again... you sound normal to me for your age and stage.
GL!
A.