This is all a fantasy. I have not yet seen ONE girl who 'passed' who was not transitioning (at least on hormones, had surgery, etc). Male and female bodies have thousands and thousands of subtle differences that everyone subconsciously just 'gets'. If someone is calling you a woman or 'maaming' you, likely it's actually out of respecting CDs/TVs, not that they actually are thinking you're GG. Not that such a thing is bad. I think acceptance is greatly needed, but don't confuse someone using specific gender references in an effort to respect their lifestyle from someone thinking they're a woman. My 2 cents...
P.S. If you are transitioning, it is possible to pass, absolutely, but it matters in terms of age, genetics, amount of time on HRT, surgery, etc. Regardless, it IS possible, and I've seen it plenty of times. Most of the subtle difference are corrected when people make that much of an effort, since it requires that much effort to be done.