I'am 16 and wanting to go to the gynecologist, but my doctor told me you're not suppose to intil you are 20.

IT depends: If you are sexually active u need to go to make sure u are on the proper birth control and have no stds. If u are not sexually active and having a problem like heavy periods or bad cramps or pain or discharge or other problems , u need to go. A good board certified gyn will be better suited to handle female problems in my opinion than your pediatrician when u are age 16.