I remember when I first entered the trades as an electrical apprentice at 21, I was told that I am too old to get into the trades and apprenticeship since most people get in at 18 after HS, a lot of it comes down to your physical ability in my opinion, this trade like most are demanding physically and I don't know if I would want to be doing this in my 50's.

When I was doing my schooling for refrigeration and gas fitting, I would say that average age was 40 in my classes, older than one would think, a couple of people were in their 50's as well.