Legal Question in Family Law in Texas

Re: How old does a child have to be to register for school without a parent?

You don't mention which level of school. Although a person needs to be 18 years old to legally enter a contract, generally, colleges will register and admit a younger person, as long as the bill is paid. If you are referring to high school, check with the local school district, as they generally require a parent or guardian, if the student is under 18.