In the traditional quinceañera court, the attendants sometimes represent the 14 years before the celebrant turns 15.
This symbolism is connected with older court arrangements that used fourteen couples, often called damas and chambelanes. The celebrant stood at the center, while the attendants represented the years of childhood that had preceded the milestone birthday.
The arrangement is traditional rather than universal. Some families use fourteen attendants, some use fourteen couples, and many modern celebrations choose a smaller court for practical reasons. The number may therefore describe a customary symbolic pattern, not a requirement for every quinceañera.
This tradition is also why descriptions of a quinceañera sometimes mention fourteen damas or fourteen chambelanes. Those terms identify female and male attendants in some communities, while corte de honor is the broader name for the whole formal group.