In golf “shooting your age” means that a golfer will take as many strokes over an 18-hole course as his age. Therefore, when an 80-year old golfer cards 80, he has shot his age.
The oldest golfer ever to achieve that feat was Mr. C. Arthur Thompson of British Columbia, Canada. In 1973 he played the Uplands course, which is 6,215 yards. At the time he was 103 years old, and he shot 103.
From The Giant Book of More Strange But True Sports Stories by Howard Liss. Illustrations by Joe Mathieu.
https://www.liveabout.com/age-shooter-records-in-golf-1563297
The youngest golfer to shoot his age was Bob Hamilton in 1975 at the age of 59.