You might check out the 50+ subforum.

https://www.bikeforums.net/fifty-plus-50/

There are quite a few riders > 60 and > 70, and maybe a few over 80.

If you have the ability, you might also look for a safer community to cycle, especially if you are nearing retirement, or retired.

I have a few neighbors in the 70+ year age range that have expressed an interest in riding, but I don't trust them on upright bikes. Maybe trikes. Age can be hard on people.

Yet, a few weeks ago I met a jolly old cyclist (70+) that lived at the top of a wicked steep hill that would certainly be a challenge for me, 20 years younger. Of course, he had a lightweight road bike, and very low gearing, and enjoyed the climb. His plan was to ride until he was 85, then retire the bike.

Distances are also important. 1 mile a week for 10 minutes won't get a person in shape.

20+ miles a day, and cycling may well have a rejuvenating effect.