I turned 65 in January, and with a little luck, I plan to keep traveling with the Minnie for 10 years or so, and then see where we're at (health, ability to travel, desire to travel, travel budget, etc.) and see what's next. If pulling the trailer becomes a problem, we're willing to explore other alternatives such as a smaller class C, or a nice B class camper, or possibly something else that will come along by then.
Glad to hear that you're still enjoying going out in the RV. For years, I've been inspired by some of the folks (older than us) that are enjoying the rv lifestyle and enjoying their retirement years and staying active! As I've always said, a moving target is harder to hit!!