This guy right here, his name is Ötzi. He died around his 50s. 5000 years ago. In the high Alpes. No, not due to old age. He was actually murdered. He was not considered ancient, just old. It's speculated he was already crippled due to past wounds - both fresh and old, and yet he was fine and rocking at the altitude of over 3000 meters... until someone penetrated him with an arrow.

No that isn't a counterargument to your theory, as a single special example is never enough to discard any statement. I don't need to, because it's already well documented how wrong this perception of aging is. I just want to show you just how durable people were even in the truly ancient times.