I ran into a few career changers (40+) during initial and two were in my class. One made it, one didn't, but I don't think older guys are having any more problems than anyone else. Age is just another number, unless you've got Alzheimer's or something.

Just make sure you show up ready to learn. And accept that you will be scheduling's b!tch until you can hold a line. That might be a tough transition coming from a place where I assume you were calling all the shots.