Full discloser this is my grandma. The same grandma made the hunting news famous when I recorded her shooting a deer with a crossbow and gutting it herself at 80 years old. She has now done it again by shooting the mile with her grandson.
Mildred Spencer has been teaching shooting safety classes through 4H for 25 years and is an avid hunter. Her grandson John-Mark Ziegler took her out to shoot the mile on Labor day. Ziegler spent 8 years in the Marines and now spends much of his time shooting long distances with his 300 WinMag. This video shows the grandkids she taught shooting safety to watch her become the oldest woman to shoot the mile.
We could not find any known records for the oldest person to shoot the mile, but there was no mention of anyone close to this making the shot.