I will be 30 starting my MFA this coming fall. I took time out of school, both in between high school and art college, and between getting my BFA ( grad. 2009) and now. I found the experience of not being a student really important for my growth as an artist, and as a person.
I've been told my age is the average for MFA's, but I always thought it odd (but not all bad!) to go straight from undergrad to MFA...at the masters level I feel you should already have professional experience under your belt, and I don't think student shows count. (sorry.)
I hope to see other folks my age in my program, although I don't discriminate based on age, just level of maturity. That's code for, I hope I'm not bunking with a bunch of kids...