So, I've been using my fem name more and more, and asking folks in the "circle of trust" to use it as well. I still have this, "No crap, that's me!" reaction. Feels wonderful.
And I struggled with choosing my name for a while. Actually, I had the same name in mind the whole time, but it was the name of an ex, so that seemed weird. That is, until I realized that it didn't matter. The name I chose fits me well, isn't some strange combination of unpronounceable letters, and isn't the same as some teenage pop star.
Anyhoo, yes, I'm certainly not "used to" my new name, but that's okay. If everyone else gets to screw up every once in a while with it, I have to give myself the same break.