Debutante : A person who makes his (or her) first appearance before the public.

Example:
What do you say during an 18 treasures speech for a Debutante?

Taxonomy
débutante, debs, débutante ball, ball, débutante balls, début, school, girls, dance, society, young lady, coming-out party, court, United States, family, lady, tradition, escort.

Defination from the web:
débutante might have her own "coming-out party", or she might have a party with a sister or other close relative. ... Débutante balls are almost always held in a reception centre or ballroom. ...