I did this, though I'm at a university. I suspect it'd be much harder at a high school where the kids tend to be insufferable about anyone who is different (no offense to anyone still in HS, but I found it torturous). For me, it was only awkward when I ran into a few students I knew from a prior quarter who called me by my old name. I just politely corrected them with my new name and when someone referred to me as 'female' I politely explained I was actually male. No one fussed about it, if anyone has issues with it, I've heard nothing about it.
I had planned to e-mail a professor who'd gotten to know me, to tell her about my transition, but the class I intended to take with her was canceled so the subject did not come up. But that'd be my primary advice, making sure any faculty/staff that needs to know, knows, so they can support you.
