I'm a 30 year old, married M1 with a 2 year old. I don't really look too much older so I don't stand out that way even though I'm like the 7th oldest person in a class of 200+.
In regards to immaturity there is a big difference between some of my peers' behaviors and what I feel like dealing with, but for the most part folks are pretty mature.
There is a lot of fun-looking socialization that I cannot go to but its no big deal since I have other things to do. I also don't need the same social support as my peers since I get that at home (and other nice perks like help with laundry, meals, cleaning, and an INCOME 🙂). I guess I would like to socialize more, but for the most part its just a no-go. As a fairly new parent I'm also sure -- ok, I know -- I talk about my kid way too much and the younger students just don't relate to that much at all.
Do I fit in? Ummm, sure. Everyone is cordial regardless of whether you go out to the bar with them or not. Is there a little bit of a divide between me and the younger people? Yes. But, honestly, it could just be me but you kind of get to a certain age and just don't give a **** anymore. We're all going to be colleagues so we're already pretty strongly linked through that... and maybe by the fact that you don't know who you're going to be practicing next to someday.
I think that age has been a factor in some cases in my ability to perform a little bit better than others in the limited clinical exposure I've had so far, but again, some of the younger people have been doing remakably well with it. I'm also handling the stress and workload better than many, maybe age/experience has been a factor with that as well.