Child Support in TX - 15 year minimum?

In my divorce paperwork (through legalzoom), I have the following language in the child support section of the Marital Settlement Agreement - "Petitioner shall pay to respondent the sum of $XXX.XX every two weeks as child support until fifteen (15) years or Respondent's remarriage which ever occurs first." Is this language correct for filing in TX? (I have heard through and acquantance that there is a 15 year unconditional minimum).