Oh yes, having watched my mother and MIL age, I'm determined not to be like them. That and maintaining weight loss (okay, losing weight at the moment) is what keeps me exercising and especially lifting.
The Extension Service office here offers a program for seniors based on Miriam Nelson's "Strong Women" books. Weight lifting for women who's median age is probably in the low 70's! (A couple of "younger" - i.e. late 60's - friends of mine go.)
"Promise me you'll always remember: You're braver than you believe, and stronger than you seem, and smarter than you think." Christopher Robin to Pooh