As others have said, it depends on your State. I knew a guy in Texas who had his gender changed on his ID years ago and even then he had to be on T, have top surgery, and a doctor's letter. Then he had to get it court ordered to be done and take the letter from the court to the DMV. For many of us it tends to be an arduous task.
If it helps ease your fears a little do know that having the infamous F on your license isn't really a big deal. I mean, I pass without a shadow of a doubt and still haven't changed my gender on it. I've never had anyone say anything when they copy my stuff for a job or anything. In fact just the other day I was at the liquor store picking up a little Holiday spirit and was asked for my ID. The guy looked at it closely (birth date is right beside gender), handed it back, and said "You don't look 32, have a great Christmas sir". Just know that if you pass at least half of the time more than likely people aren't going to study your identification. There aren't even many instances that you really have to show it, so don't stress too much about it if you're not able to get it done for awhile.