depends what social group you are in
my and my mates...some of us have girlfriends, others don't, the ones who don't aren't going round getting laid all the time, I live with 2 lads who are virgins (as far as I know). They aren't social recluses, they go out and have a great time.
I think the problems come when students think they should be getting laid every five minutes but aren't, and start stressing about it. It's not a sign of maturity having casual sex with people you don't really know, it's a sign of immaturity and trying to get something out of upping your numbers of sexual partners which you will never get (unless you're trying to get an STD)