What should I do? :(

TW: Transphobia

My brother was in my room talking about "how stupid it is that they made Hawkeye nonbinary" and while I agreed, my reason is that we should make more non-binary characters instead of making existing characters non-binary and he agreed because he doesn't understand non-binary people and therefore makes fun of them.

My mom then calls him into the living room but not me so I just overheard it but she says, "why are you talking about that?"

My brother responds with something like, "because it's stupid?"

My mom sighs and says, "does this person have a penis or vagina?" And then my brother says that he has a penis and then my mom says, "then it's a boy"

Then to rub dirt in the wound, she says different masculine pronouns, terms, etc and I'm just listening here.

So safe to say I definitely am NOT coming out (not that I was really thinking about that as something to do before)

Plus if she finds out, idk what she'd tell me.

When I said I was a demi girl because I didn't understand the term genderfluid so I felt I didn't align with it, I was being manipulated by someone who happened to have identified as nonbinary so she thought I was being manipulated into believing I was that.

So idk what she'd think now because that person is now cut out of my life. Maybe she'd think the Internet was influencing me or something, which I don't want because then she'd take that away.