I wouldn’t worry too much. I started as an OS at 56 with a bum right knee and hip. Half the people I work with are my age or much older. I’m the youngest AB in my click. The oldest is 67 and stills climbs and works like he is 40. Hell, we all do. We all have the same problems, bad back, shoulders, feet, eyes, hips, ankles, knee, etc… And most are pretty chronic with other age-related health issues.
I sailed for a year with a rather large AB with a prosthetic leg. That was 2 years ago and he was 62 years old then. He didn’t have a problem with any of the work, including climbing ladders lifting/hauling heavy cargo and wearing SCBAs during fire drills. He is still sailing…smokes cigars chases women where ever he goes and loves to drink…too much. In foreign ports, I would follow him around because he knew where all the easy fun was.
Maybe that is the secret. Cigars, booze, and women.
Buy boots one size too big or for more comfort, over-size steel toe sneakers. Adjust with inserts…or not. I don’t. By-the-way, We had a Cook and Cheif Eng that wore steel toe slippers.