It’s okay for first intercourse to be underwhelming. If it is, you can rest assured that you didn’t blow a “one-time-chance” at eternal bliss. It just doesn’t work that way. For pretty much EVERYONE who engages in intercourse, or any kind of sex, it’s safe to say that their first time is more likely to be their MOST unfulfilling time (physically, and sometimes emotionally) than the opposite, and that’s often the case no matter your age or station. Think about your first kiss, for instance. Chances are, though, it’s less likely to be really disappointing if you do a reality check with your expectations and your feelings first. And every time you have a new partner, it very much is like having a new “first time” all over again — we get lots of firsts in life. Don’t make yourself bananas over one that wasn’t what you’d hoped, or attach a bunch of symbolism to how it went: for instance, because the sex was ho-hum means your relationship is. Much of the time, part of the reason our watershed experiences are rites-of-passage is about not the experiences themselves, but what they teach us.
From Is THAT All There Is? here