I don't think it is necessarily comical to watch young love, since there are certainly some that are genuine. From my college experience though, it is highly irregular. I do know some people that stayed together and got married though, including myself (actually mine has been since high school), but it is by far the exception.
Most college students are not mature enough to really know what they are getting into, and thus it just makes me shake my head when I hear it.
I got married at 23 and I do not think that is early at all, it all depends on the person.