Mia,
Does your school or district have a parent group for gifted? Is there a gifted coordinator at your school or district level? Do you know any parents that have older children identified and have been throught the system.
You can move, homeschool, private school. Those are all great options.
If your principal is managing you, and I think you are right that the numbers show how intelligent your child is and that you have not been hothousing, you might be able outmanuever him/her with a little help.
Example, our district actually has a set policy about skipping and the principal has to follow the procedure. But if you don't know what the procedure is, he's not going to volunteer that information.
Maybe you can find out if others have approached the skipping subject with that principal and what his/her reaction was.
Good luck