If it doesn't go well don't lose hope about having a good relationship with your mom. My best friend had it a bit rough when she came out as trans too but her mom has since become really accepting of her and they have a great relationship now, honestly even stronger of a relationship than they had before she realised she was trans, her mom seems to quite like having a daughter now.
Her relationship with her dad admittedly hasn't really recovered unfortunately, at least not yet.
The commercial says that Church isn't for perfect people, I guess that's why I'm an atheist.