You are so right @jayna, it's our life, so we have to do what works for us. Why retire simply because one has reached a certain age; some people are ready to retire in their 50s, others not.
I've also heard of way too many who die soon after retirement.
I worked for land surveyors for most of my life and because their job entails working outdoors, and doing much walking, many lived long lives and continued practicing way past the so-called 'retirement age'.
My last boss, before I joined our local council, still does calculations in his home office, at the age of 92, while his son and staff do the field work! Mr. H also was an avid golf player, which means a lot of walking.
He came to my hubby's memorial service and still is chirpy and full of life, truly a legend!
So, why stop doing something one enjoys, and still have the freedom to take breaks without seeing that kitty shrink?
But, we need to start walking, that's the big secret to a healthy life ;)
You do what is right for you!