Chosen by the inner sanctum of the Rex Organization, she is usually a junior in college at the time of her reign — 20 or 21 years old. Amidst a whirl of Carnival-related events and obligations in the weeks and months leading up to her day in the limelight — tea parties, debut parties, social calls, dress fittings and lessons in the finer points of royal protocol and etiquette — she’s supposed to keep the honor a secret.