subdebutante

noun

1. A young woman who has not yet made her formal appearance in society.

   “This is the season of the subdebutante. These are the days when in shrill perfumed coveys they flutter through the houses and clubhouses of America's big cities. When summer comes they will disperse to the leisure of lakes, beaches and mountains. But now the subdebutante is dynamic, gregarious and at the peak of her plumage.”