I'll weigh in. My experience has been a bit different from what's been posted above.
I'm one of the youngest people in my class, but I've always been mature for my age (I'm 25 as an MS-3, but I'm married with a kid too, etc). My experience has been that there is indeed a sort of "rift" between the older and younger members of the class. Superficially, the older students will mingle with the younger ones but they don't usually form any sort of substantial friendships with them. (There are exceptions.) Furthermore, I've seen a lot of older nontrads who seem to feel as though they're...just "better" than the 'youngins' because they have kids and stuff to juggle with school, etc. This attitude has reached a fervent, almost obnoxious pitch at times, and I'm personally somewhat sick of hearing it - I'm young, I have a kid too, I get how stressful it is, but I'm not constantly wearing it as some sort of red badge of courage. I'm more like the older students in terms of my outlook on life - I'm not into partying and drinking myself ******ed - but I'm one of the younger students in terms of age, so I don't really fit well into either group. Many of the older students with families are only interested in spending the minimum amount of time on campus, and they run off asap at the end of the day to be with their families - which I get, but it doesn't help the cause of class cohesion one iota.
What I'm trying to say is that while I'm indeed friends with some of the older people in the class, there's definitely discrete groups of "younger students" and "older students" around here, and they don't always mix all that well. This may or may not cause problems for you socially, but expect to see evidence of it.