Should I just freakin' tell her already?

I'd just pull her aside before class and explain my trans status. Chances are, no matter what time you pick it will always be awkward - now or later. So the sooner the better, right? Plus psych teachers are probably going to be more cool with trans* people than the usual breed so it shouldn't be a big deal. Or, if you don't want a face-to-face you could email her, as I hear that is a common method for coming out to teachers while at college.

 

If you're really being affected by the fact that you're trans and your teacher refers to you as sir, then absolutely. You should come out, like Rhys suggests. Pulling your teacher aside sounds like a good idea, but I would personally bank on sending an email. If you do it before a class or something, your teacher might have to cut you off in favor of doing something else, and the worst thing that can come of that is the teacher recognizing that you're trans but maybe not recognizing that you're not out (unless that's what you want).

If you send it in an email with everything important you need to say, the teacher gets to it when they have the time to do so, will read the whole thing and understand what you need from them. If you feel like it needs more discussion, close it up with 'If you have any questions, feel free to ask'. It opens a window for them to find out what makes you comfortable.

If you're not comfortable coming out, maybe just send an email saying you're not comfortable with sir for personal reasons? I don't know if the teacher won't get the idea as to what those personal reasons are. But it depends on what you want to tell them.

Good luck!

 

You should definitely tell her if it's bothering you so much. Whether you tell her in person or via email, keep calm and be polite. Do you know how she feels about gender identity? I think it might be a good idea to try to figure this out before you decide to come out to her. If she's not open-minded towards this issue, there's the risk that she may not treat you fairly after comming out to her.