Is expiation obligatory upon one who swore an oath not to marry while a child, then wished to marry after reaching puberty?

If a person takes an oath before the signs of puberty appear or before reaching the age of fifteen, their oath is not binding, and there is nothing upon them. This is based on the Prophet's (peace and blessings be upon him) saying: "The pen has been lifted from three... and from the child until he reaches puberty." For expiation to be obligatory, the oath must be binding, and a minor's oath is not binding before puberty.