Protection of employees is weaker than anywhere else in the US. The Northern Mariana Islands have been accused by the US Federal Government and various other organizations for enslaving foreign workers (particularly from China and the Philippines) and immigrants in sweatshops and prostitution.
It can be as low as 18 or as high as 21 depending on where the child lives. In Delaware, the age of majority is 18. However, almost all states allow the child, a parent or a guardian ad litem to write to the judge and/or petition the court for modification of the original custody agreement.
On a fairly regular basis I am asked by a divorced parent how old their child must be before they can choose which parent they want to live with. Many parents tell me their child will be 12 years old, 13 years old, 14 years old soon and will be able to make their own decisions. They appear to be uniformly surprised to learn that a minor child does not have the legal right to decide which parent to live with.