Well, I did it. Like it says in the title, I came out to one of my best friends the other night. I'd been meaning to do so for about two years now, but never could find a time when it seemed appropriate. I know when you've known someone a long time, there is a grieving period afterwards, and I've know this friend for like a decade and a half. Moreover, they've been having a rough time themselves the past few years, so I was afraid any grieving would further contribute to their problems, and held off until I felt I had to. Well, the past few months I've been making a point to tell more people, and this was their turn.
They took it well. Actually, all of my friends so far have taken things well, though admittedly I've prioritized telling the ones who I've thought would. Still... Anyway, there was an aspect of coming out that surprised me: They already knew (or at least strongly suspected), and had been waiting for me to open up about it, for like three years now.

I didn't think it would be a huge surprise, but I didn't think anyone was actually
expecting it. Apparently, my mannerisms are
really feminine, not in an effeminate gay sort of way, but in a girlish way. They said that if you actually know what to look for, it's kind of obvious I'm not a cis-guy. In fact, my friend told me that when we've gone out to eat, I apparently raise the pitch of my voice when talking to the wait-staff (without realizing it), and one time when I left to go to the bathroom, the waitress asked my friend "where did the lady with you were with go?" I guess I give off a womanly vibe.
Not to segue too much, but afterwards I talked with my mother about my mannerism, and she also thinks they're feminine. Apparently, I also do a lot of hand gestures (again without realizing it) that are feminine as well. And my voice is high for a guy. Which itself isn't necessarily a part of one's mannerisms, but it does fit in with the whole read-as-female package, what with the long hair and soft features and all.
Anyway, I feel better now that things are open between us, and I can be more honest about what's going on.

Plus, I decimated them in Tetris Attack, and that's always a good feeling.

One more down, two (three?) big ones left to go.