Ok, because the original order is from Mississippi, that State law applies to when support termination ends.
Under Mississippi law, a child is not considered emancipated for child support purposes until age 21 unless the child:
Marries, discontinues full-time enrollment in school at age 18 or older (unless disabled), joins the military and serves on a full-time basis, is incarcerated for committing a felony, or cohabits with another person without the approval of the parent obligated to pay support.
(Miss. Code, Title 93, Chap. 11 Sec. 65(8)).
Since your daughter will be remaining a full time student in college, emancipation
does not occur until age 21 (or if she quits school or one of the other factors that trigger emancipation).
I hope this answers your question.
Please keep in mind that information in this forum is for informational purposes only. It is not legal advice and does not constitute creation of an attorney client relationship. Before acting on any such information, you are always advised to consult with an attorney licensed to practice in your jurisdiction who can take the time to review all the facts and laws relevant to your situation.