At your age you (hopefully) have many more years to cary a gun!! I am 70 and still schlep guns around.
A few things make age easier. You need to make certain that your gun fits you very well. Then, recoil is no problem. People who complain about recoil or truly get beat-up shoulders mot often have guns that are poor fits and they have adapted themselves to the gun rather than the other way around.
One of my favorite guns is the Merkel 1620. It's a 16 ga built on a 20 ga frame. It is superb and I can carry it all day without fatigue. It is lighter than my 20 ga Merkel.
It's also good to try to keep fit - I am not an exercise fanatic but I "train" on my elliptical a few months before I go on a big hunt and it really makes a difference. Losing even 5 or 6 pounds makes a big difference, too.
Screw age! Keep on trukin'
