The teenage girl celebrating her 15th birthday is called the quinceañera.
The same word is widely used for the celebration, so its meaning depends on context. It can identify the honoree herself or the event held in her honor. In English-language writing, the spelling often retains the ñ, although simplified spellings appear in informal contexts.
The quinceañera is usually the visual and ceremonial focus of the occasion. She may wear a formal gown, enter with attendants, participate in dances, and receive symbolic gifts. Customs are not universal: one family may include a church service and elaborate court, while another may hold only a reception.
The word is feminine because the traditional celebration honors a girl. A boy’s comparable celebration is commonly called a quinceañero, although terminology and practices vary. Neither term requires one fixed religious ritual or party schedule.