The number traditionally written in a quinceañera’s name is 15.
A quinceañera conventionally celebrates a girl’s fifteenth birthday. The Spanish word quince means fifteen, so the name directly identifies the traditional age. Depending on family, country, religion, and local custom, celebrations may include a church service, formal clothing, a court, a reception, and choreographed dancing.
The practice is especially associated with Latin America and Latino communities in the United States. It is not a single standardized ceremony: families often adapt the event, and some celebrate at a different age or omit particular rituals.
The tradition should also not be treated as a universal legal declaration of adulthood. Its meaning is cultural and familial, while legal adulthood is determined by the laws of the relevant country or state.