The reason for this is that all eyes will go to the birth day girl on that special day.
Then the family orders a cake that is special like a wedding cake. Next, the parent rent a hall for the party and rent a band to play music. After that, they decide on the special food to serve the guests. Often a Quincenera celebration can cost as much the girl's parents can afford.
The hall is beautifully decorated with flowers, and it is full of guests. They wait for the girl and her family to arrive. The band plays music, and the party begins with a dinner. After the dinner, the girl dances the first dance with her father. Then the other attendants start to dance, followed by the guests. It is a day she will always remember.