Welcome from another octogenarian.
I had very little musical education as a youngster other than church choir singing, school operettas and the usual Welsh spontaneous group singing.
I decided that, having got my OBE (Over Bluddy Eighty) elevation, I might as well indulge myself with some larnin' and bought myself an accordion and the "Accordion Method" book by father and son Galliano.
Having watched a number of utoob videos by eminent classical and jazz players I opted for 5 Row B systen Chromatic Button Accordion patly because it would be easier on my arthritic hands than the contortions required of a piano style keyboard.
In retrospect, choosing the C system would have been preferable since there is a lot more instructional material available in the English language.
Others here will undoubtedly chime in on the matter of instrment suitability for this, or that, but for me, in my blissful ignorance, it seems that ultimately is it whatever suits you best, rather than the specific design purpose of the 'box' wwhich really matters.
Living "Far from the Madding Crowd" as I do, I have been restricted to watching carefully on the 'webs' the ways in which the really competent musicians go about their playing, leading me to the conclusion that itis more about the musician than it ever is about the instrument.
Of course, with all its attendant limitations, age is secandary to your state of health and stubborn determination to cope with them.
Good luck, and go for it