The Spanish word traditionally describing the girl celebrating her fifteenth birthday is quinceañera.
The term is feminine and is derived from quince, meaning fifteen. In ordinary usage, quinceañera can refer either to the celebrant or, depending on context, to the celebration itself. English-language communities commonly use the same Spanish word.
A male celebrant may be called a quinceañero, but that term describes a different gendered form of the word. Dama refers to a female member of the ceremonial court, while chambelán commonly refers to a male attendant; neither word means the birthday celebrant.
Spelling varies in informal English, including quinceanera without the ñ and accent mark. The Spanish spelling quinceañera is the standard form in Spanish-language writing.