it is all in the mind

Life begins at 90 from bbc

"Fauja's jogging skills were developed on an Indian farm in Punjab, and then at the magical age of 81, when he moved to the UK, his love for the sport became more "serious"."
...
"So any secrets to fitness? Fauja's training regime includes a daily eight-mile walk and run, no smoking or drinking, plenty of smiling and lashings of ginger curry. "
...
"So, having only run seriously for the last 13 years, when does Fauja think he'll trade in his spikes for a zimmer frame?
"When I die!" he laughs. "

it is never too late to start doing what you want :)