What was the description of the clothing of the Prophet's daughters (may Allah's prayers and peace be upon him) and the daughters of his companions or the Tabi'in, and what was the description of the clothing of young girls in the جاهلية (pre-Islamic era)?

A girl at the age of three is not required to cover her head because it is not considered awrah (private parts that must be covered). There is no harm in accustoming her to the hijab from a young age. There is no mention in the Prophetic guidance of a specific attire for the daughters of the Prophet, peace be upon him, or the female Companions and their successors, during their childhood, nor for young girls in the pre-Islamic era of Jahiliyyah. Guardians must prevent girls who are approaching puberty from tabarruj (displaying their adornments), because a father is responsible for his flock, and he must prevent his young daughter from tabarruj if she is desired, out of fear of fitnah (temptation or discord).