One of the original spurs to the creation of the Green Bubbie concept was the physical move of my mother-in-law into our home over 3 years ago. At the time, she was in her late 80's, and as I was becoming a grandmother in my own right, I began mentally charting the differences in being a 'grandmother' and a great-grandmother.
On a purely numerical basis- health aside, I would say a green bubbie is anywhere beginning in your 40's 50' or 60's and easily stretching into the early 80's. As 5o becomes the new 30, I would say that from my vantage point 80 plus to 120 is beyond the scope of what I mean as a 'green bubbie' There are always exceptions.
For me 'green' means young, new and pliable. Just as in a twig or branch, if it's green it is very much alive and capable of new growth.
I also want to put forward the idea that there are probably a good 30 years for a green bubbie to grow and sprout new roots, nurture and thrive.
Stay tuned for my 'hole in the bucket list' video coming to a you-tube near you.