I turned 42 last month.
I have been thinking about that a lot. The average American lifespan is 78.8 years. Obviously there are highs and (unfortunately) extreme lows that skew that, but I had grandparents that lived to 91, 88, and 83. I am pretty healthy, so getting to the 84-85 range is probably pretty reasonable, and maybe a few more with medical advancements over the next few years.
Still, I am roughly halfway there. My bones ache a little more. It takes a few extra moments to get going in the morning. I am sitting on multiple foot surgeries in my lifetime and could need more later.