There's a new category of mystery to try out: "Geezer Lit." AARP Bulletin points out this genre with great appeal to a graying Ameria. The crime solver is over 50 and often much older. There may be a mid-life crisis or a new love involved. A good sense of humor is important as well. Just the titles will get you chuckling. I think much of the appeal relates to dealing with aging parents as much as our own gray hairs.
Here are some possibilities, but a google search will bring up many more!
Mike Befeler--Retirement Homes are Murder
Cynthia Riggs--Shooting Star
Parnell Hall--The Sudoku Puzzle Murders
Rita Lakin--Getting Old is to Die For