I am not sure what is going on in particulars but considering the vagueness I recommend that you:1. Ask to consult with your parents first if you are a minor before you do anything you are uncomfortable with, in this case, signing a witness statement.2. Review your school handbook with your parents if you received one (most do at the beginning of a school year which the student and guardian both sign) You or your parents may as for a copy of it from the school if you no longer have it3. If your parents are wary about you signing anything they should consult a legal professional.