I agree that 80+ seems to be when things start to go downhill, although there are alway exceptions. It's hard for me to believe that just 12 years ago my parents were helping to take care of ME, ( I was on bedrest for a high risk pregnancy) and continued to help with my son for a few more years. Now my father is dead, and my mother is totally dependent upon me for transportation, taking care of her medical needs, paying bills, shopping, laundry, etc. My father was very active until 80, then fell off a ladder and broke his hip. It was a downward spiral from that point on. My mother fell and broke HER hip 3 years ago; same story.
Watch your diet and exercise regularly, all you youngsters!