I'm half-way out. Not out yet, but nearing it; I began the process, but I can't get myself to say the words. Instead I just stumbled around the topic and went to another trans-related topic.

My grandma is always saying stuff like "Do you think you're a boy?" or "I think she thinks she's a boy", just because I cut my hair and refuse to wear earrings (I told her I wanted studs; plus a lot of girls have short hair and don't wear earrings).  She doesn't sound positive about it either.
One time she basically called me out on this, I started bawling and she let me cut my hair for the first time. 

I'd rather not come out, but I want to at the same time. It sucks.. But anyway, I already began the process so it's near impossible to stop. I just have to keep going forward with it.

I know my mom would be fine with it, but everyone else is a blur for me.

Try bringing up the subject without implying that it has something to do with you.  Like, tell them about something you saw in the news relating to trans people.  See how they react.

"Hey, guys, did you hear? Bono's kid has gotten a sex change. Apparently, Chastity is now Chaz."

Something like that ought to work, tweaked to your situation.

If they are true friends it won't matter. If they are just peers, what does it matter?

Jennifer

I know how you feel about your grandmother; every time I visit my grandmother, she pesters me constantly about why I don't have a boyfriend, or why I refuse to wear dresses or anything feminine.

But, in regards to seeing how people react, I agree with just bringing up the topic, but referring to a third party instead of yourself. You may feel like they can see through it, but generally, they probably won't think that you might be talking about yourself. In all the times I've done that, that's never been the case. Good luck, though!

(By the way, awesome avatar!  )

Same here. I try to be more masculine, but I just look more androgynous. My mother has asked me if I want to be a man, and I couldn't tell her anything. 

Good luck with your mom.