Rachael:
Going out is a choice that we all deal with sooner or later. If "passing" is your sole objective, be sure that your confidence level is high. Ask yourself this: If I went out and someone looked at me and laughed, how would I react? If your answer to this question is that you would feel humilated and ashamed and want to run into a corner and die, then it's not time to go out yet.
I like to practice in drab in public. I practice my facial expressions, my walk, voice, body movement, etc... I love it when I am dressed as a male and someone callls me ma'am and then corrects themselves and calls me sir. I think you need to give it plenty of time and when you are ready to go out, you will know it. There is no rush.