Jack,

If you are serious, I would look around for a martial art school that caters to someone your age and fitness level. That doesn't mean that you have to be in shape. However, the teachers will need to talk with you about your goals, class expectations and will likely require a physical signed off by a doctor attached to the liability waver. If you are obese or a senior citizen, then you might be able to find a Tai Chi class, but this won't get you far.
If you go to some schools, they'll expect you to run laps, and require training similar to military basic to one degree or another. You should call around and pay for a week or two worth of classes, then narrow your choices.
Very few schools get into weapons for a long time.
Wright down your goals, take notes at every class and you'll go much further with less expense invested as you search.

Are you seriously interested in martial arts and developing self defense skills?
Do you live near a big city?

Last edited by Happy_Camper; 01/13/21.