I went back to my old high school today to see one of my teachers. Throughout my senior year she'd been urging me to go on to college, because I showed reluctance to continue my education. This summer I finally admitted to myself I was trans, etc. etc., and now I understand why the idea of more schooling didn't appeal to me; I'm not comfortable having to live any more of my life as female. So I decided I might as well come out to her, seeing how she had given me her number and told me to call her if I ever needed help. And if I ever needed help at a time in my life, it's now.
We met up after school, and I followed her into a photography teacher's classroom. While she was in a back room, taking pictures for the Homecoming event, I was waiting out by the computers.
Eventually these girls walked in and came to sit by me. One of them asked me if I was the photography teacher's son. I didn't realize I passed that well, so I was kind of surprised. I just laughed and said no, I wasn't related to him, and that I was just visiting an old teacher. They then started trying to guess my name. Saying stuff like Anthony, Gregory, etc. I was like, "There's no way this is really happening." But it was, and it was awesome. So I told them my chosen male name.
I was trying to be mysterious and not reveal my age or what school I went to, because I honestly didn't know what to say. They kept pressing me for information. It made me wish I had thought up something to say in case that happened, but I hadn't counted on seeing anyone else.
Halfway through all this, I realized my teacher would eventually come into the room and call me by my birth name, so I ran into the back room and told her, "Look, I'll explain this more later, but everyone out there thinks I'm a boy, and that's great," and she nodded and said "If that's okay with you it's okay with me." I went back out, thinking I had averted a crisis.
It didn't work though. A little while later she came out and went, "All right <painfully obvious female name>, we're done here--"
Everyone looked at her like, "What?!" She realized her mistake and said "Oops...I meant...<passably male version of my female name>." Which still isn't the name I had given them. But we were both laughing so it probably confused them even more. When she went out into the hallway they rounded on me and asked what my name really was, and I just repeated my chosen name. I caught up with my teacher and she apologized for the slip-up, but I wasn't too upset. Well, I was, but worse things have happened, and I'm not going to see those kids again. I might as well not worry about it. I'm just trying to imagine how they'll refer to me amongst themselves...and really, I should have told her to call me by a specific male name, because how else could she have addressed me if I didn't let her know?
We went back to the classroom with a bunch of other students to work on this project, and any time she referred to me as my birth name or female pronouns, they'd do a double-take and look really confused. That was really surprising to me, because like I said, I didn't know how well I passed.
But yeah, we finally got the chance to talk to each other alone. Coming out to her was really easy. She took it totally in stride and gave me some sound advice, and hopefully I'll be back again soon to talk to the guidance counselors and stuff. I'm counting today as a victory, even if I did get outed, because I didn't expect to pass in the first place.

She also said that as soon as she saw me today she caught on. Not just because of my haircut, but because for the first time since she'd known me, I was standing up straight and looking people in the eye. She said I looked happy.