Your teachers will probably be pretty understanding. I started transitioning my last year, and I told my old advisor (who had been my professor for three years) and she didn't miss a beat, or even bat an eyelash.
I lived on a college campus for three years, was considered an "non traditional" student as I didn't start college until I was 20, and my husband was a college counselor for four years, so as for how to not embarrass yourself, I would give this as advice: They are just as nervous as you are about people's perceptions of them. On top of that, most people actually don't really care and I would use that to your advantage. If someone calls you a girl, or female pronouns, just look at them confused. A raised eyebrow or something as simple as a chuckle and joking it off works wonders. Last time I was called "miss" by someone on my old campus, I looked around, realized he was talking to me and laughed. He was actually more embarrassed than I was and when he apologized I just replied with "Nah, it happens a lot. The curse of late blooming, y'know?" Bear in mind that this was a university that I was pretty well known at, because of the husband's job.
So, that is my advice: Everyone is nervous and they are just as stressed as you. Most people are actually not out to be malicious or hurtful, and the best you can do is to just try and be a person.