When my mother’s mother, who was on no meds and had never been sick in anyone’s memory, was in her 90’s we were leaving a family gathering and she announced she would be dead within the week so goodbye to all of us. Several told her she was being silly; there was nothing wrong with her. She said didn’t matter. God told her she’d completed everything she was tasked with doing here, was done, and time to move on. Of course no one took her seriously. She caught a cold a couple days later and was dead by the end of the week.
I know it isn’t up to me but if it was up to me, that’s the way I’d want to go out. No specific age. Just don’t leave anything unfinished and don’t hang around without purpose. Finish and leave.
More likely I’ll be tortured stuck in a nursing home irritating everybody for years or I’ll die early choking to death on a Moon Pie or something equally stupid.
Right now I still have stuff to do and a few people to take care of. Just want to finish. And then leave.