In 2018, 80 is the most common age for an American (U.S.) Dorthy who is registered female with the Social Security Administration. It is the 1, 774th most common female first name for living U.S. citizens.
This is my real first name, but I go by my much more contemporary middle name. All the same, I catch a lot of flack from it on the first day of school - people always comment on how old school it is and make Wizard of Oz references! But it's my granmother's name, so I'm proud of it.