I will be 37 when I begin residency, with NS being the field I am focused on. Why so old? An M.S. in one science field, a Ph.D. in another, and 2 yrs of PostDoc will do that to you. ...oh, and 4 yrs of med school as well. =)
Actually, this isn't as old as I thought it was. The program I have my sights set on has quite a few older residents. I have a friend in this program who is currently an R3-NS resident tell me, "No matter what ..... always maintain your academic curiosity and enthusiasm, it's a lot of fun when you're close to seeing the end of the line".