You might be asking why she is dressed like a princess. It’s because she is 15!
Quinceañera (pronounced: [kin.se.aˈɲe.ɾa]; feminine form of “fifteen-year-old”), also called fiesta de quince años, fiesta de quinceañera, quince años or simply quince, is the celebration of a girl’s fifteenth birthday in parts of Latin America and elsewhere in communities of people from Latin America. This birthday is celebrated differently from any other as it marks the transition from childhood to young womanhood. (Wikipedia).