20 at uni to a (nice) long-term bf (his 1st time also) I had met there, which was exactly how I wanted it to happen to me ie quietly, with someone I liked who was both responsible and respectful.
My decision as I recall, after I had decided that 20 was old enough! Also, I was very curious about what sex was like.
Sadly for me, it wasn't anywhere near as good as I had expected it to be, so I was left quite disappointed by the whole thing. But I loved him, so we carried on for a few yrs after that. (Then we both moved on without any regrets.)
I did gradually realise later on (after a few more bfs) that sex probably wasn't/still isn't really my 'thing' as it wasn't getting much better for me. (So I probably shouldn't be blaming my partners!)
I always liked being in a good relationship, and I liked the intimacy. (Just not the sex act itself.) So a bit of a balancing act on the sex front.
Wish I found sex more fun, (as most on here seem to really enjoy it so much), and hoped it would eventually get better for me, but we are all a bit different and maybe we shouldn't compare ourselves too much? (Cos I think that's just how I am. And can't change it.)
I currently have a very kind, loving DH, and nice (adult) kids, so it's all good on that front. Plus I have never had a 'bad' sexual experience ... with anyone. So, overall, I feel lucky with my sex life to date, even though sex itself has (usually) always been a bit boring for me.
We build sex up so much these days so I do have some envy for those who love it, but I reckon it's not always good for everyone. (And certainly not always great for most people all the time?!) So we should be more realistic about what is possible for ourselves, and just try to get pleasure from life whenever and wherever we can?
In retrospect, I wouldn't change when and where and with whom I first had sex. But admit that people with a higher sex drive than me might have found it hard to wait till 20!