okay so I'm not sure what to do.

I came out to my mom as bi...my dad doesn't know anything.
my "boyfriend" came out to me as transgendered and I'm fine with that.
I came to the realization that i'm a lesbian, but haven't told my parents yet.

my girlfriend doesn't mind if I tell my mom I'm a lesbian but then I'd have to out her. I'm not sure how my mom feels about the whole transgender thing and am not sure how to bring it up to find out. I wanna come out when the time is right, but I wanna know how she feels about transgender people first.

Any ideas?