You are right. She was a dancing appliance at age 18
Gotta start somewhere. ;-D
It’s curious that when she was 16, she tried out for the role of Danny Thomas’s eldest daughter, Terry, on “Make Room For Daddy.” He didn’t hire her because of her “petite” nose, saying she wouldn’t resemble a daughter of his (Marlo did look a bit like her, but she later got a nose job to resemble Mary !).