Fu: A hair clasp for tying hair. Ancient women were engaged at the age of fifteen, and they tied their hair and wore hairpins that year; Those who are not allowed to get married will wear hairpins at the age of twenty.
The Book of Rites says that "a woman ... has been married for five years". "Cue" means to tie a knot in your hair and use it to penetrate it.
It means that you are old enough to get married.
A woman promised to get married, but when she did, she was praised. -"In the Soul of Li Yi's Poetry"
In ancient times, when a person was twenty years old, a coronation ceremony was added to show that he was an adult. Han and Liu Xiang said to Shuowen: "If you are crowned, don't be an adult ... When a gentleman begins to be crowned, he must wish a gift and be crowned with Li Qi's heart." Later, because of his coronation, he was twenty years old.
Etiquette for the coronation of an ancient man when he was an adult (twenty years old). The coronation ceremony was held in the ancestral hall, presided over by the father, and the young people who performed the coronation ceremony were crowned by the designated VIPs. In other words, a woman 15 and a man's 20 can get married. However, most of the ancients were precocious and married early.