Hello Tony.

It's one thing to talk the talk (about retiring at a ripe old age). Better is what you've done (taking the time to look up the actual number in years). 

There's no argument about the hard numbers. You cannot count them backwards. They are what they are; and numbers count.

In some cases, 79 years old is all about badly insufficient numbers of gray brain cells. In many cases, the strengthening of the white brain cells connectivity (which is responsible for the wisdom of experience) makes up for lower gray brain matter. However, in a substantial minority of cases the gray cell die-off takes a terrible toll (in terms of the ability to keep up with basic responsibilies).