The last doll symbolizes leaving childhood behind in a traditional quinceañera.
The doll is presented as a symbolic reminder that the celebrant is moving from childhood toward a new stage of life. In some ceremonies, a parent or sponsor gives the doll during the reception, and the celebrant may pass it to a younger sibling or another child. This creates a visible connection between childhood and the responsibilities associated with growing older.
The custom is not universal and is often adapted or omitted. It is also different from the changing-of-the-shoes ritual, which uses footwear to represent the transition from childhood to young womanhood. These symbols can appear together, but they are separate traditions.