Without seeing a picture of your face, I don't know if your jaw looks "masculine" or "feminine" - so I can't really comment on what your friend may or may not be seeing.
As for T, My face shape changed in a massive way at about the 7 month mark. I had a fat, round face with a smooth roundish jaw - when the fat in my face redistributed, my jaw was much more pronounced and square-looking - also because the area just under the eyes and between the cheek bones and nose sunk in a great deal, it made a startling difference.
On a side note, I agree with the others - I have seen men with smooth, indistinct jaws and women with strong, square ones.