I started transitioning this year and I'm in my third year of high school. It's a really tiny private school that has everything from infants-high school and this is my fourth year there. I basically just came to school binding the first day, informed my school counselor of what I was doing, gave a short note to each of my teachers saying that I'd put a different name on my assignments, gave a note to the principal, and then gave letters to some students I'm close to. All but one of my teachers calls me by the right name and pronouns. The one who doesn't just forgets most people's names and doesn't really care about anyone, so it doesn't matter. The principal actually held a faculty meeting to talk about me, during which it was decided that I get to use the faculty restrooms, which are unisex and much cleaner.
I actually thought that there would be more resistance. In the past, there've been a few students who said that they supported the Holocaust simply because the Nazis killed homosexuals. But it seems everyone's either pretty okay with all this, or they're afraid of what would happen if they weren't okay with it. I'm completely openly trans, but I'll occasionally find someone who has managed not to notice and insists on calling me like a girl, but people will usually correct them.