I have seen Betty White on television several times recently and she seems to be doing great at 91.
great at 91, and her mind is as clear as a bell. I think part of it is that she is still working and seems to be very active. On the other hand, I think some people just assume that since they are getting older that it is time to shut down, and act "old". I think a positive attitude and keeping busy can make a huge difference in the way a person ages.