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.
Does anyone know at what age a child can choose which parent that they want to live with in the state of Iowa when there is no court ordered custody set up? Probably what ever the Iowa's age of consnet is, or perhaps 21. Regardless call your local public library.