Keep It Playful
Knowing that there will be a day, that you will not be able to perform like you can today. I suggest that you practice/play jiu-jitsu at two intensities; first is to take everything and give nothing, Second is to be able to flow with whoever it is you are training with, to take from everything, even your losses. To appreciate the art to a level that when you start being defeated by people that you expected to defeat, you still smile.
If you would like to share the mat with your grandchildren the same way my grandfather did with me, the keepitplayful approach is the only way.