Nobody is going to teach you the attitude.
You can’t duke it out, you can’t flee.
per John Wayne aka J.B. Brooks
Friend, there's nobody up there shooting back at you. It isn't always being fast or even accurate that counts. It's being willing. I found out early that most men, regardless of cause or need, aren't willing. They blink an eye or draw a breath before they pull the trigger. I won't.
This is very important IMO. I went through a lot of thought before becoming a gun owner (at age 67!), along the lines of would I be able to actually shoot an assailant with no hesitation.
I agree with Jeff, there is not going to be a class that lays out exactly what every senior has to do in a self-defense situation. If you have unlimited funds you can get a personal trainer to work with you, but honestly you are the person you're going to have to depend on in a Situation, chances are you can also figure out what changes you have to make compared to how you may have done things in the past, as luzyfuerza said in post #32.
Regarding physical issues, just like you figure out how to do other things you can no longer do the same way as you used to, you can figure out how to do what you might need to do in a self-defense situation. I'll share my experience with this below, if it helps anybody great, if you think it's dumb, just ignore it.
I already had some physical issues at the time I started shooting, but OTOH I never thought I have to do everything the exact way other people do. The first thing was, in my first handgun class they wanted us to use Weaver stance, which due to multilevel degenerative disk disease in my lower back was painful for me. What my body wanted to do was to stand firm with feet roughly shoulder width apart but facing straight forward and knees slightly bent, at the time I just told the closest instructor I can't do it the way we were instructed, and he said ok, don't worry about it. <shrug>
I was living in Cali at the time and carry permits were not issued to regular people, but by then crime in my neighborhood was already pretty bad, IOW my gun was going to be for home defense. I mentallly went through possible scenarios and figured out what I would have to do, then dry-fire practiced them. For example, my bedroom was at the front of the house, the construction of the windows made security film useless, and I did not want to install bars. So a BG breaking in through one of my bedroom windows would have been inside my bedroom a few feet from me in a couple of seconds. I could not (and cannot) just jump out of bed and immediately do something physical (much less roll off onto the floor and then kneel which I guess would be the standard recommendation), so I decided I would have to stay in bed and be able to shoot from there. Trying different things I found I could fire slightly turned from being fully on my back with one knee raised. I dry-fire practiced that
a lot. I worked through all the other scenarios I could imagine in the same way.
Of course, on the street there are an infinite number of scenarios and a person can't rehearse every single one. But however many you can think of, figure out what would be the best response that you can carry out in your current condition, and practice that, and you'll still be ahead compared to just putting on your gun when you get dressed.
I think maybe the two most important things are your situational awareness, and how fast you can draw and get on target. I am hard of hearing and do not hear somebody walking up behind me, so in transitional spaces I keep turning around to look. But before entering a transitional space in the first place I look to see if anything looks out of the ordinary, and if I have any doubts I stay where I am until they resolve, or if I'm in my car just drive away. Re drawing, you have to actually practice using the carry method and position you plan to use on the street. Fortunately you don't have to go to the range for this. I check myself before leaving the house by drawing once or twice while looking in the mirror. I found a slight adjustment in the angle of the holster made a huge improvement.
So, my $0.02.