Damn that's a tough question oldest retired pro wrestler that's still alive?
Maybe Johnnie Mae Young (born March 12, 1923) a former female professional wrestler.
The youngest is pretty darn hard as well, maybe Katsuhiko Nakajima (中嶋 勝彦, Nakajima Katsuhiko?, born March 11, 1988) is a Japanese professional wrestler, represented as a freelancer by his mentor Kensuke Sasaki's Kensuke Office. He most frequently wrestles in All Japan Pro Wrestling, where he is a former AJPW World Junior Heavyweight Champion.
I do know the oldest currently wrestling is Gilberto Melendez (born December 2, 1933) is a Puerto Rican professional wrestler better known under the ring name Gypsy Joe. Currently he wrestles for the Southern Wrestling Federation in Tullahoma, Tennessee.
So I guess If I got the other 2 wrong 1 out of 3 aint too bad, I'd like to see if anyone has a clear cut answer.
Good Question, I starred it!
EDIT: I assume when you say pro-wrestling you mean all federations, not just WWE, that would be easier,
Mae young would still be correct, Colin Delaney (born September 7, 1986) is actually younger than Cody Rhodes and the oldest to still be wrestling in WWE is The Undertaker Mark William Calaway (born March 24, 1965), unless you count Vince as a wrestler then I guess he is (born August 24, 1945).