If you are 18 but not graduated high school yet can ur parents prevent you from moving out in Texas

No, your parents cannot legally prevent you from moving out or doing whatever else you want to do once you turn 18 (assuming they don't have a guardianship over you because you aren't able to manage your own affairs). They may be concerned about the possibility that if you move out, you'll drop out of school and/or just have trouble taking care of yourself. A little parental backup might be nice to have if you do run into problems, so before moving out, you might consider whether some kind of compromise could be reached.

No, but you really, really should finish school.

I agree with the other attorney's answers. Your move-out cannot be prevented but you should consider finishing high school , at the very least.