Has your mom ever considered that God might have made us to represent the variety and diversity of human gender expression? I am sure you have explained this to her, but I explained to a friend that Lady Gaga's song "born this way" can still be okay for me, (I am agnostic) but I think if God did in fact create us, they could forsee the amazing diversity humans would become. People's skin, hair and eye color all span a huge spectrum, our minds and bodies ALL work completely differently, while still following a fairly standard (ish) model. If God created people to be born with different bodies, heights and weights, why not genders and sexualities. The universe is so complicated we cannot possibly assume anything about what the creator had in mind (if there is such a way to describe God's mind).
What is God created those people with BID to blind themselves? What if they aren't sick, they really just don't need that body part? WHO ARE WE TO JUDGE AS JESUS SAID. Also, isn't there a line or two about plucking out thine eye and such? I can't say. You can't say. They can't say. We all just are.
In a less philosophical vein, you are a friggin soldier to put up with that. You are a beautiful, strong person and you can get through the love that hurts. I know it's painful and awful, but it's something that you can use to strengthen your resolve. If the people you love and are close to you can't hurt you anymore, then a stranger you care nothing about can't hurt you.
Finally... we have modern medicine and it's not going away anytime soon. Ask your mom if God believes in Pacemakers, Hearing Aides, Pills that support life functions, Cancer therapy? Have you told her that you feel God loves you as you and is not going to condemn you for medicating yourself as you see fit?
If she doesn't, then at least she is consistent in her dogma. Any professional and person not blinded by hate disguised in dogma can see that a Transgender person suffers more from their society's prejudice than anything else. I can't say that the people who were/are accepted or not stigmatized in non Christian societies were/are perfectly, always happy (like any other human being) but I imagine their pain was/is lessened by being allowed their own space to be themselves.
Regardless of what she thinks, I am so happy for you to be on T and knowing/finding out who you are and having the courage to do what you can about it. It's a hard journey any way you go, but I hope this is a good way for you to go. Don't forget there we are here for you as much as we can be!