Unlike most sports, which you simply cannot play as you age, you can keep playing tennis and improving throughout your active life.
I have been playing tennis most of my life. I do not play that often and occasionally miss months at a time but I keep it going. I also play with people at all levels. Previously, I played competitively, taught professionally and coached top ranked junior players. One thing proven to myself is that my tennis playing is improving as I age. I cannot say that my present game would be able to compete with my former competitive self or with today’s players at my former competitive level…but Iam a much improved player. I know now much more about what kind of ball is being hit to me and what to do with it. My strokes are better and my ability to handle pressure, disppointment and success is way better. So overall I think I am a better player.
One reason for this is I was taught and learned good fundamentals. Good stroke fundamentals together with practice result in a more sure and accurate shot. So …certainly you can improve your stroke production as you age. But it is not essential to have the best strokes. Even with quirky strokes, if you keep playing and practicing, you will become a better player. The mantra for success at any endeavour is not talent or ability but to put in many hours of playing and dedicated practice.
Aging does limit your ability to move quickly. However, although you may not get to as many balls, when you do get there you can be in a better position, know what to do with the ball and strike the ball better to a better place. This means your tennis playing is better.