Oh, that is a tough situation! I completely understand being sympathetic with her, since it sounds like she is under a fair amount of social pressure, and probably has her fair share of unexamined biases. I think it's possible to feel for her, and to also insist that she treat you as the man you are. Your gender isn't a choice that you made. It's not something you can or should change to please other people. But being closeminded is something she has control over, and it's pretty unfortunate that she would prioritize her friendships over her relationship with her son.
Or, to put it another way: she's showing you who she's chosen as her family, even if she won't admit it. The beauty of transitioning is that it comes with a wonderful loving community of people who will choose you as family if you so desire.
I hope you are able to find your family.