Green’s Dictionary of Slang

1. (US Und.) a woman serving her first jail sentence.

1935

A.J. Pollock Und. Speaks 30/1: Debutante, a female serving her first prison sentence.

2. someone new to the gay lifestyle.

1941		G. Legman ‘Lang. Homosexuality’ in Henry Sex Variants I 524: [H]is bright blue eyes and pink cheeks of ten years ago, which made him a popular debutante in New York’s homosexual circles, have given place to the lesser physical attractions of maturity.
1965		K. Marlowe Male Homosexual 89: The big event of the year is the debutante ball. That’s when new members who have never been ‘brought out’ can make their debut [Simes:DLSS].
1975		N. Jennings' Chicken Lickin’ 23: Holmhurst yawned. ‘Excellent for a debutant, baby. Now it’s been a long day so if you cocksuckers want to grab last one kiss, kiss it good night and I’ll be leaving’ [Simes:DLSS].