In NC, you have to change things first with SS, then the DMV. The rules on gender markers in our state is also surgery required, just as it is with SS. My therapist told me a few years ago that they did have a rule change for the state at one time a number or years ago, but it was killed off about a day after it went into effect and no changes for the better since.
But luckily, so far, it hasn't been much of an issue for me to have M on my license with my female name, most people seem to overlook that since they're looking at it to verify your name or age, not your sex.