Because of Islam's great love for marriage, it has strongly emphasized that people get married as soon as possible.
The custom of early marriage is upheld by the intellect and the religion. It was the norm amongst Muslim from the dawn of Islam up to and before the cultural, economic and military assault by the laws of the west and East upon their lands.
Getting married early is the prescription of the prophet for some of the toughest challenges that face the youths and have an enormous impact on the well being of the society.
Ibn mas'ud (R.A) reported the prophet (S.A.W) to have said
" O young people! Let those of you who can afford marriage get married as it will help them lower their gaze and protect their chastity. And for those who can't afford it, they may fast, for it will curb the sexual desire (Bukhari and Muslim).
However, the definition of " early" itself varies according to circumstances. Notice that the Hadith says " who can afford marriage" which is to afford it in every regard. In all nation's, people got married earlier than they do now. In Europe, during the time of Shakespeare, if a woman was single at thirteen, she was considered late for marriage as reflected in his writtings.
Islam doesn't imposed a specific age for eligibility for marriage and leaves it for the legal authorities to decide the proper age for marriage in order to maintain interests of both husband wives.
This of course changes from one country, community to another depending on many considerable factors.
Pls kindly up vote and re steem for others to benefit. Thanks