Of course US citizens can get in state tuition. And the rules for them are much easier than for the illegal kids that the Feds refuse to allow us to notice, much deport.
They have to live here one year, not 3, and can be graduates of any high school, not just a Texas high school.
(a) In general
Notwithstanding any other provision of law, an alien who is notlawfully present in the United States shall not be eligible on the basis of residence within a State (or a political subdivision) for any postsecondary education benefit unless a citizen or national of the United States is eligible for such a benefit (in no less an amount, duration, and scope) without regard to whether the citizen or national is such a resident.
(b) Effective date This section shall apply to benefits provided on or after July 1, 1998.
Search 8 U.S.C. § 1623 : US Code - Section 1623: Limitation on eligibility for preferential treatment of aliens not lawfully present on basis of residence for higher education benefits
Perry needs to be asked about this soon.