Unless the circumstances dictate otherwise, child support payments shall terminate when your child:
Dies;
Marries;
Enters active duty in the military;
Becomes self-supporting, provided that the custodial parent has relinquished the child from parental control by express or implied consent;
Reaches age eighteen, unless the provisions of subsection 4 or 5 of this section apply; or
Reaches age twenty-one, unless the provisions of the child support order specifically extend the parental support order past the child's twenty-first birthday for reasons provided by subsection 4 of this section.