What can I say that has not already been said?
I think at "our age" (which is quite broad to encompass all TE members) the most important thing is to: keep moving!
You find not only the physical health benefits...but how it makes you feel inside. How you look at the world. How you look at YOURSELF.
That is what counts. So if you walk, run, bike, row or whatever it is that keeps you moving--do it. No mater how slow or unsteady it may be.
I have many of times wanted to create a cycling jersey with a tortoise on it. I am slow, but steady and I'll get there eventually! And sometimes quicker than those that go fast! (believe it or not!)
Welcome!