When I e-mailed my professors, I framed it as an issue not only of comfort, but of safety. Y'know..."I'm a guy, and that's what I'll be telling my peers. If someone in authority says otherwise, I could face verbal or physical harassment. I hope you'll help me to avoid that possibility." They're unlikely to refuse if you put it that way. I was just as worried as you, and have gotten nothing but support from my professors. And I'm in Tennessee. Just ask them to reply to your e-mail asap so you know they've received it, and if any of them reply saying they can't call you "he" (which I would hope they would have the decency to do, on the off chance that ends up being the case), maybe it'll be with enough advance warning that you could switch to a new class.