We all age at different rates and I don’t think the number is as important as the wear and tear we put our bodies thru getting to whatever age it is we are at. I see guys in their 50’s, 60’s and sometimes 70’s still riding low drops with no pain or issues. That wasn’t the case for me and through a good number of used bikes when getting back into riding around age 50 I learned a lot about self-fitting that’s not in the young guy at the LBS vocabulary. In my case the legs, lungs and heart are all cooperating pretty well still, but like you the neck, back, wrists etc. were my limiting factor. The solution was more upright the problem was the hybrid bikes didn’t seem to fill the needs I had ether. I read a lot on the topic and found for me more of a “French Fit” helped along with figuring out how to move drop bars up and back to counteract the reach problem. The biggest thing I found out that took the most pain away was saddle position front to back. With moving the saddle back against all intuitive reason to move it forward when trying to take strain off the neck and get a slight bit more upright balanced me better on the bike and the core took over much of the support of my upper body. Taking the strain off arms and shoulders allows the neck to work a lot better.
So for me I hated drop bars when I first went back and after figuring out drop bars can be higher than what most people would recommend. I then got the benefits of all the hand positions. The hoods are a most relaxed place now and I find myself in the drops more than half the time now. When I’m riding I take note of where most people have their hands and almost no one older is riding down there most are on the tops or hoods and I see a lot stretching like they are fighting getting upright where their body naturally wants to be. My one friend asked me how can I ride all day in the drops and I pointed out my drops are almost as high as his hoods and he gave me a puzzled look.
Nothing wrong with drop bars but don’t be afraid to experiment with stems and height.