Moms.
Emotionally invested, biologically invested and tied to the hopes and dreams of being proud of their progeny.
For her it will have opened a whole raft of questions, and concerns. How did I miss this, what were the signs, how did I not create the right physical body, is it something I did, did I do something wrong, am I being punished and more.
Just as your world was rocked by the discovery of your true self, hers has been rocked, because all that she had done so far, and her imagination of a future (giving hope), has been rocked.
As a dutiful daughter, you know how much impact that has had, and feel guilt. You would also do anything for your mom, even if that means trying to deny and remain living as a characature.
Transition does not make us trans, and it is not something to be hurried. Breathe, relax, talk with your therapist, take your own sweet time and then decide what you want to do.
Sno.
*edited to fix typo