No matter how old your children are, you can still collect back child support.
There are many different ways to collect back child support unpaid child support. For example, you can collect back child support by garnishing wages or by seizing property. Both of these methods are available forever. There is no “statute of limitations” on using them.
The Texas Supreme Court, the highest court of appeals in Texas, put it this way in a case called In the Interest of A.D.:
In 1974, the only means available to collect unpaid child support were contempt and a money judgment. Later, wage withholding became available, no matter how old the missed child support payments and no matter how long the non-paying parent had avoided his or her court-ordered duty to pay child support.
In that case, the children were 32 and 26 when the mother began child support collection. In other cases, the children were in their 50s and 60s. It simply does not matter how old the children are. If there is missed child support payments, even if it’s adult children, then they are owed back child support that includes interest.