The literal Spanish meaning of “última muñeca” is “last doll.”
In a quinceañera ceremony, the última muñeca symbolizes the end of childhood and the celebrant’s movement toward adolescence and adulthood. It may be presented by a parent, godparent, or another significant family member during the reception.
The tradition is one of several symbolic moments that families may include. Other examples can involve a special toast, a religious service, a formal dance, or a presentation of jewelry. The exact sequence and meaning vary among countries, regions, and individual families.
A literal translation does not mean the young woman is receiving her final toy forever. The phrase refers to the symbolic “last doll” associated with childhood, not a rule that she can never own another doll.