Texas Transportation Code - TRANSP § 521.203. Restrictions on Class A and B Licenses

(1) is under 17 years of age;

(2) is under 18 years of age unless the person has completed a driver training course approved by the Texas Department of Licensing and Regulation;  or

(3) has not provided the department with an affidavit, on a form prescribed by the department, that states that no vehicle that the person will drive that requires a Class A or Class B license is a commercial motor vehicle as defined by Section 522.003.