I started when I was 32, about a month after I quit smoking. I had gained a ton of weight, and had gotten very aggressive, and needed a way to vent some of that funky energy.
I'm 43 now, and the body, I swear, is in worse shape now than it was when I started, but I think I'm paying a special pennance for a dissolute youth, rather than suffering from any glorious Aikido injuries.
I felt like the old guy when I started, and I aint feeling any younger. Unfortunately, most if not all of my sempai and my teacher are older than me, and most are in pretty good shape, so my excuses have to be other than age related.
I wish I'd started Aikido at a younger age, or at least been better to my body when I was young. Wasn't it Mark Twain who said " If I'd known I was gonna live this long, I'd have taken better care of myself"? Or was that WC Fields?