Living behind the mirror

Living behind the mirror

I remember I once read or saw somewhere that as part of a fantasy history, that mirror were actually the doors or windows to an alternative universe, an universe where everything is the other way around.
And there were those were the difference was simple, like on one side the subject was left-handed as opposed to right handed, or the reflection was a good-samaritan while the main character was the evil villain, or that the real world person loved to eat pizza, while the alter ego hated it, preferring instead to eat pumpkin pie.
To those more complicated, for the alternative universe was totally different,and even if the person looked exactly the same at the mirror, in one world she was single while the reflex was married with 5 kids, or being an office worker while the alter-ego was a lion-hunter in Africa, or the king of the bizarro world.

And I wonder, if by some weird literary experiment I would try to do the alter-ego on the other side of the mirror of Jessica.
How would that other me be??
And which of my many appearances would it be? or Would it be all of them?
And if indeed the world of the mirror is the opposite, could it be that there being feminine is the usual?
And that dressing male clothes is what is considered the weird crossdressing?

Kisses
Jessica