The right age for grand-parenting

I couldn't remember my grand-parents, they had all passed away when I was a toddler, but I remember that my Dad was in his 80s when my kids were toddlers and my Mom and by parents-in-law were all in their 70s.

What did it meant? Just that they were already too old to enjoy their grand-children and play their grand-parent roles with them. It was already too late as they no longer had the required patience nor the natural motivation anymore.

At my age, being a grand-parent still works fine, but I need to do it now, without having to wait for an extra decade!