I went from "Nat" to "Matt", and the very first time I heard "Matt", I reacted like that had been my name all along, since it sounds so close. However, it's been months now, and only a few people call me Matt in person. Due to health problems, I can't bind, and my voice hasn't seemed to change at all yet, so at work I still haven't "come out". Despite me saying I prefer my new name, my mom still calls me by my birth name. So I've had this new name for over 6 months now, and I still feel uncomfortable when people use the name. Every time I hear it, it makes me aware of everything going on in my life and it all just feels so wrong.
I'm getting top surgery next month (Feb), so I'm hoping once I'm able to get most people calling me by my preferred name, it'll get comfortable much more quickly.
At least, I really hope that's how it happens. :/