I am turning 18 soon. My younger sister is 16. I want to become her legal guardian. Is this possible.

Once you turn 18 you are entitled to apply to become the guardian of your sister.  The problem you have is Texas law establishes a hierarchy (by statute) of persons who should appointed as guardian of a ward - particularly, a minor ward.  In this case, your parents would be the first persons on this list and you would be third behind them.  Unless you can prove that they should not be your sister's guardian, i.e., that is not in her best interest that her parents be appointed as guardian, then you will not be successful in your endeavor to become her guardian.  You will have to, essentially, show that your parents are unfit as parents.  This is extremely difficult and would be very expensive from litigation costs. Your inquiry makes the entire situation sound very simple - unfortunately, it is not simple and not inexpensive. I hope this answers your question(s). Sincerely, Kevin Spencer www.spencerlawpc.com