Marrying at a young age has many side effects.

First, if they are paired with older men, like in the olden days, when these men pass on, the women are left stranded. So, they have to remarry in order to have someone who can provide them with means (lands, etc) to feed their children.

Also, they stand a risk of dying during childbirth due to the underdevelopment of their reproductive organs.

So, many have ended up with tears that makes it difficult for them to keep in urine. There is how this is called in medical terms.

Which points to why child marriage should be discouraged, especially among girls.