In the state of Texas, any child aged 6 through 18 years old must attend school. Given some specific exceptions, no student can quit school until the age of 18.
The laws that require students to attend school are known as compulsory education laws. The exceptions to these laws that allow a student to not attend school are the enrollment in a Texas Academy of Leadership program, the student being expelled from school or a disability that doesn't make attending school feasible. The compulsory education law is not limited to public school attendance. Private and home schools are other options available.