I've put off writing this for a few weeks now, sorry about that.
Alas, it turns out things were not going as well as anticipated. The day after the events described in my last post I received a phone call from my step father telling me that my mother wasn't taking things as well as she appeared to be the day before. He implored me to talk to her, but she refused to speak to me.
This continued for another week before she opted to call me. The following conversation was... balanced. She was supportive one sentence, but antagonistic the next. Her use of names and pronouns was inconsistent, and she again voiced disapproval for my chosen name, clothing, and urged me to not come out to people.
It's been a bit of a haunting position, to not have the complete (or real) support of my closest biological relative; it just makes me more dependent on the support of my friends, and I'm not entirely sure if I have that either.