Quinceañera is the usual Spanish feminine term for the teenager celebrating the event.
The word can identify the young woman herself, not only the party. English speakers also commonly use quinceañera for the celebration, so context determines whether it means the celebrant or the occasion. The term is formed from quince, meaning fifteen, with a feminine ending associated with a girl or young woman.
Other Spanish words describe participants in particular roles. A madrina is commonly a sponsor or honored adult, while a dama may be one of the female attendants. Those terms are not synonyms for the celebrant. Local usage can vary, especially in bilingual communities and modern celebrations.
The term should not be interpreted as a legal category. It is a cultural label tied to a fifteenth-birthday tradition. A family may also use quince años or simply quince to describe the event, while quinceañera remains the most recognizable term for the celebrant.