Octogenarian
A person who is old enough to have seen your parents when they were kids and still has the balls to tell you that you're doing everything wrong.
My aunt is an octogenarian and still tells me I'm doing everything wrong.
My grandpa is an octogenarian and still has the balls to cuss at me for no reason.
My neighbor is an octogenarian and still remembers when the internet was a thing that only rich people had.