I got married at 24, and my wife was 23. We're happily married, and we've had the benefit of growing together, rather than apart. That said, we've talked a lot about how we'll advise our children when they get older, and the conclusion is currently, "wait until you're at least on the other side of 25."
We know our planned advice sounds funny, since it's obviously not what we did, but, based upon what we've seen among our friends who got married before 25, we'd be remiss if we told our kids we think it's a good idea. Offhand, I can think of half a dozen couples I know who got married pre-25, and only two (including us) are still together. The stats bear out our anecdotal observations, too, since getting married before 25 is one of the factors that's often cited as a "risk factor" for divorce.
I'm currently in the 28-35 range, and thus so are many of my friends, but it does seem to be the sweet spot so far.
That all being the case, I really can't argue that it's wise to get married young(ish). Some folks will make it work, but the odds just don't favor it at all.