Actually it depends on a country, as legal age can differ.
However I really would not like my son to bet married even at 18, let alone 15 or 16.
That would really be a nightmare. I
guess such early weddings are sheer lack of education from parents. So I want my son to go there and start dating different girls first. And he must learn how to use barrier contraceptives to avoid not only getting married at 15, but getting AIDS at this age too.