FWIW, Tyger, I had sex for the first time at the tender young age of... 31¼. And I'm not ace.
I'm just a guy who wanted my first sexual experience to be with a woman who loved me. Not one pissed off at her boyfriend and looking for revenge sex, not one just drunk and horny, not one who wasn't sure but might have been susceptible to pressure.
Alas, then I found that sex was majorly overblown as an experience. For me, anyway. I enjoy the post-coital moments much more than the orgasms (if I even get them) because it's just me and the woman I love, together.
Cuddling is also very nice. Nicer, actually.
Also hard to beat wine, great pizza, and a good streaming movie, cuddling on a couch under a blanket with a fire going.
Or... sorry, lost track, where was I going? Oh, yes, some non-aces also don't experience sex until later. And end up wondering what all the fuss was about.