Is it permissible to sell a gold gift that was given to a baby girl when she was young and no longer fits her, and to benefit from its price?

A mother is not permitted to dispose of the property of her minor children unless she has been appointed as a guardian by the father or by the ruler. This is because guardianship over the property of minors belongs first to the father or his appointed guardian, then to the grandfather, and then to whomever the ruler appoints. If the mother has the right to dispose of the property and deems it beneficial to sell the gift, its price must be safeguarded for the daughter and spent on her specific needs.