We pay until 21 - unless we can prove they can support themselves- marry or go into the army. I've also heard if they are in college we will probably have to continue until they are out of school.

Not sure where you are from, but this is missouri
2. The obligation of the parent ordered to make support payments shall abate, in whole or in part, for such periods of time in excess of thirty consecutive days that the other parent has voluntarily relinquished physical custody of a child to the parent ordered to pay child support, notwithstanding any periods of visitation or temporary physical and legal or physical or legal custody pursuant to a judgment of dissolution or legal separation or any modification thereof. In a IV-D case, the family support division may determine the amount of the abatement pursuant to this subsection for any child support order and shall record the amount of abatement in the automated child support system record established pursuant to chapter 454. If the case is not a IV-D case and upon court order, the circuit clerk shall record the amount of abatement in the automated child support system record established in chapter 454.

3. Unless the circumstances of the child manifestly dictate otherwise and the court specifically so provides, the obligation of a parent to make child support payments shall terminate when the child:

(1) Dies;

(2) Marries;

(3) Enters active duty in the military;

(4) Becomes self-supporting, provided that the custodial parent has relinquished the child from parental control by express or implied consent;

(5) 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.

4. If the child is physically or mentally incapacitated from supporting himself and insolvent and unmarried, the court may extend the parental support obligation past the child's eighteenth birthday.

5. If when a child reaches age eighteen, the child is enrolled in and attending a secondary school program of instruction, the parental support obligation shall continue, if the child continues to attend and progresses toward completion of said program, until the child completes such program or reaches age twenty-one, whichever first occurs. If the child is enrolled in an institution of vocational or higher education not later than October first following graduation from a secondary school or completion of a graduation equivalence degree program and so long as the child enrolls for and completes at least twelve hours of credit each semester, not including the summer semester, at an institution of vocational or higher education and achieves grades sufficient to reenroll at such institution, the parental support obligation shall continue until the child completes his or her education, or until the child reaches the age of twenty-one, whichever first occurs. To remain eligible for such continued parental support, at the beginning of each semester the child shall submit to each parent a transcript or similar official document provided by the institution of vocational or higher education which includes the courses the child is enrolled in and has completed for each term, the grades and credits received for each such course, and an official document from the institution listing the courses which the child is enrolled in for the upcoming term and the number of credits for each such course. When enrolled in at least twelve credit hours, if the child receives failing grades in half or more of his or her courseload in any one semester, payment of child support may be terminated and shall not be eligible for reinstatement. Upon request for notification of the child's grades by the noncustodial parent, the child shall produce the required documents to the noncustodial parent within thirty days of receipt of grades from the education institution. If the child fails to produce the required documents, payment of child support may terminate without the accrual of any child support arrearage and shall not be eligible for reinstatement. If the circumstances of the child manifestly dictate, the court may waive the October first deadline for enrollment required by this subsection. If the child is enrolled in such an institution, the child or parent obligated to pay support may petition the court to amend the order to direct the obligated parent to make the payments directly to the child. As used in this section, an "institution of vocational education" means any postsecondary training or schooling for which the student is assessed a fee and attends classes regularly. "Higher education" means any community college, college, or university at which the child attends classes regularly. A child who has been diagnosed with a developmental disability, as defined in section 630.005, or whose physical disability or diagnosed health problem limits the child's ability to carry the number of credit hours prescribed in this subsection, shall remain eligible for child support so long as such child is enrolled in and attending an institution of vocational or higher education, and the child continues to meet the other requirements of this subsection. A child who is employed at least fifteen hours per week during the semester may take as few as nine credit hours per semester and remain eligible for child support so long as all other requirements of this subsection are complied with.

All states are different. What state is the order from? By the way, I have read of lazy SKIDS who's CS should stop at 18 or graduate from highschool, whichever is later...and the NCP files 60-90 days before the idiot turns 18...guess what the idiot kids do? If they hardly attended before 18, they start attending as soon as their CP is notified by the courts...which of course, extends it...hmmm...watch out...we are in the same boat...