I don't think there's anything special about sex. It's just sex. More fun and meaningful with the right person, of course, but a relevant part of growing up and understanding yourself, self-confidence and your interactions with others regardless.
I don't subscribe to the suggestion that one should wait for marriage, because I don't think everyone should get married. 2 mature people with true self-understanding can commit to each other or a family without a ceremony of piece of paper from the government.
Caveat: most people are immature and never develop a true self-understanding. These people should probably get married if they're going to have kids, and should hold off sex until then if they can't handle it otherwise.
IMHO...