You could also see if you could switch schools, and present as female at the new school - I've worked in one of the biggest school districts in the country, and I can tell you that as long as you are in a place with multiple schools, you should be able to find a way to go to any school you choose, either through the school district itself, or by simply lying about where you live (using a friends address, grandparents, relatives, etc.).
I went to a school that was literally opposite side of town from where I should have gone to school, where I lived. We just lied about where we lived, using a friend's address.
You may or may not lose friends - you can always keep in touch with social media and just hanging out - but switching schools, depending on your town, could allow you to present as female from the get-go at a new school, where nobody knows you. I suppose where you live definitely matters though. Less populated places wouldn't allow for switching schools. The tolerance in the area towards trans people is also another issue, considering some staff at least probably have to know about your status as trans. Maybe not if you can get your gender legally changed, if it's possible where you live.
Also, you could just stay with the same school and go through with it. The people insulting you are probably going to end up having very crappy lives after high school. That's mostly what happened to those jerks after my class graduated
, and it's only been 7 years.
If you act with confidence, you can get through it just fine. There was a MtF transgirl at my high school (with over 2000 students), and nobody really cared, they accepted it and were fine with it. She passed pretty well too.
