It takes longer for your internal mental image of yourself to change than your body, or so I've heard. This seems like a common problem, of course I'm no expert, haven't even really started yet, just somebody that's spent way too long thinking about this and researching every aspect with my strongest Google fu.
I'd try some mental exercises, I think the new agey term is "mindfulness"
I've been working on things myself, up until about two weeks ago I'd refer to myself in my head with male pronouns instinctively, I've internalized acting male to such a degree that it required an effort to break, now I don't need to think twice, it's always correct, just have to be careful when I talk to people I'm not out to now...
It's certainly a more advanced thing to try to change your self image though, I'd say first you need to learn to quiet all of your internal talking, and then go a bit further to quiet those thoughts that are there but aren't expressed by a voice yet, and once you're blank, imagine up your current self image, and change it to your ideal one, alternatively if it's easier create a narrative depicting the morph, or however you want it to happen, maybe the old image is locked away in the same cell the new one has been contained in for so long, or perhaps they get along great and coexist hand in hand. The details are up to you, this is the type of mental exercises I do to change myself on such a base level though...
Being transgender is not a choice, but transitioning absolutely is. Certain things like this don't match up, we all went through something when we were very young that essentially forced us to transition our self image and internal voices to the wrong gender. Now you just need to undo that, but only you know what that means.
