From the last guy you should take advise from.
This one is for you, high school boys.
Tell the teachers and other students that you are now a female. You don’t have to act differently, you don’t have to speak differently, nothing. You are now a female, tell them that is just what you identify as. So what if they point out you have a penis, you feel that it is there by mistake.
They by law (maybe, I don’t know) and at risk of offending anyone can’t say anything to you that counters your new feelings toward your own sexuality.
Now you can take advantage of the all the spoils of being a teenage girl. After gym class you go to the women’s locker room and you get your peep on. Girls may be creeped out at first, but hey girls get over it. This is 2015 and being a man but saying you’re a woman, THAT IS OK! If anyone raises a fit just threaten them with a protest or going to the media. Nobody wants to be that person on the news being insensitive to sexuality.