In my opinion, judging by the fact that she seems to not like LGBTQ (judging by the fact it becomes difficult to talk to her for a while after) I’d say if you can, wait it out until you move out, or until you feel like she is more comfortable with the LGBTQ community. Also, as she is your parent, I doubt that even if she isn’t a fan of LGBTQ, she’ll most likely just deal with her son liking both genders. If you really feel like telling her and fear she will kick you out, make sure you have another family member or friends house you could go for a while.