Lost it past the age that most people lose it, and I think I was fairly cognizant about the whole process so I have a bit to say.
Before having sex, I felt like it was a big deal. But after meeting someone I came to care a lot about and spending a lot of time with them, I came to realize that virginity itself wasn't the "big deal". Rather, what I really cared about is having that intimacy with them. So things moved steadily forwards and those inhibitions concerning virginity I had in the past were slowly peeled away. Something parallel happened with them as well: being a person with a more conservative upbringing, they had more inhibitions about it than I did, but over time she eased into the idea of having sex naturally. That, or our hormones finally got to us.
After having sex for the first time, I felt like nothing really changed. Practically no perception at all. Personally, I feel kind of pissed off at society for giving people the impression that losing one's virginity is this kind of transformation or rite of passage because for me it really wasn't. As for them, they felt somewhat guilty about it for a while, as a conservative upbringing might do to a person, but over time they came to the same conclusion: that having sex doesn't change anything.
I don't doubt that for some people, having sex entails a feeling of transformation, of crossing some threshold. The more you personally invest yourself in such an ideal, the more powerful that ideal could be. If having sex on the wedding night is all you've ever imagined for yourself, and is indeed what you end up doing, riding off the high and emotions of planning and having the marriage could make sex a truly transformative experience, I have no doubt of that. But the key word here is could, and at least myself (and some others here I imagine) can attest to being disappointed, however slightly, that what "society" claimed to have in store simply did not hold up.
Consequently, in the vein of what Shining Raichu said, don't regret losing your virginity for its own sake because not all expectations are realistic. If the first time isn't amazing or what it was cracked up to be, well it is what it is. You've already had your expectations shattered, so I really don't see the point of perpetuating those flimsy expectations further by regretting the experience too much. I think the regret would be better directed towards thoughts like "I should've thought for myself more" and things of that nature.
As for the idea that sex being something amazing that you should only share with someone you love, I feel it's like the FedEx arrow: once you see it you can't unsee it. I'm probably attractive and socially skilled enough to attain casual sex sooner or later if I chose to do so (most people are, despite their own insecurities), but I wouldn't because sex within the context of an intimate relationship seems infinitely better. Although I admit casual sex appeals to me to an extent, I would still rule it out even if I was single given what I have experienced so far in life. However, I don't believe my experiences speak so much to the virtues of sex within a relationship, but rather the value of having a satisfying intimate relationship in general.
so uh tl;dr a good relationship is awesome, and prepare to be disappointed by losing your virginity (or not and go all in it's up to you)