Thanks for all the feedback, girls! I'm going to just keep using my voice as best I can, without trying to ever revert to my old voice. I did have another situation today, since I had to teach my second class of the day after posting my thread earlier; I was a little more successful at first, but then I felt into an in-between voice and couldn't get out of it. And because it's a discussion/lecture class, I'm talking often. And so I guess my other problem is vocal stamina, sort of--I need to learn to use my female voice for long periods of time without my voice going hoarse, as it tends to, or dropping back down to male range from fear.
I'm finding I can maintain the voice better in front strangers or close friends. I used it at a Starbucks without a problem and with my office mate before I taught, but I think it's the 30+ undergraduates making me the most nervous, for whatever reason. It's not so much that my voice passes as female as that I can keep it in a more andro range in some situations, but I just need to be able to convince myself that the positives of potentially being embarrassed outweigh the negatives of never getting past my masculine voice.
Would you girls say you found your female voice over time and through trial and error, or did any of you just find the right tone one day and were able to work towards it quickly? I'm also nervous, you see, about having people hear my voice transition, especially if it sounds bad at first. I'm just a very shy person in general, and so a lot of things like that unfortunately weigh on me.