Here are some exercises that you can try if you are getting into training over the age of 50. They're pretty good for any age, covering strength, core, and balance.
The problem with approaching fitness only as a means to an end is that there is no end, no limits, and no one to say what is right and wrong for you but you.
It's a scientific fact, it's never too late to commit to movement, and strength, and flexibility, and mobility, and fitness. Your attitude is all that counts.