Depends on what you eat to be honest.
Your body stops being able to store calcium after age 30. So supplement up when young.
Your body has cell senescence, there is a limited number of times your cells can divide. Anything other than skin (and perhaps liver?) can actually never regrow. Any muscle and subcutaneous damage is pretty much permanent and just gets filled in by scar tissue. I do think numerous surgeries is going to decrease your life expectancy. The way I see it is actually a quote from the Hobbit "Getting old is like spreading butter too thin over toast, scraping and scraping." The more damage you accrue and the more cell lines start to die out it requires the remaining ones to pick up the slack in old age. Eventually you are just spread too thin. I'm 27 and look about 20

. I don't have bad knees or bad elbows or whatever since I've avoided pretty much any injuries. I'm not the rambunctious type who hurts themselves all the time by playing rec sports too rough or whatever.