How does a woman transition from a woman, to a woman, to become a transwoman?

It's more about how they never felt like their birth gender, but biologically speaking they were men. I'm not on board with them overreacting over language as people who arent fully absorbed in the trans community would not know about the finer implications. However this is a very touchy subject for many trans people though so I would advice not to poke around too much. They already have to deal with a lot of smug people. 

Sort of like those pesketarians who are againt factory farming but have people who dont know their reasons, give them crap for eating fish 

I get that point, they may have been born a biological male while they felt like a woman. There are studies that show MTF trans people have similar brains as biological women. So your point makes sense that way if you’re talking about the brain. 

What the hell are you talking about? You sound really confused.

You are correct that they are already women but we use the word transition because they transition socially from man to woman and most transition medically as well. 

Apparently you don't understand how transsexuality works or what it means to be transgender.

Cisgender women and trans women are both female, so there is no need for her to transition.

They don’t.....       .

If she is a cis woman then there would be no need to transition to a woman,  obviously.

If were a ftm guy and decided that they were a woman after all then that would be referred to as detransition.

You can't transition from a woman to a woman, if you are already a woman.

She doesn't. She was a woman, and specifically a transwoman, all along.

She can transition from a woman with a penis to a woman without a penis by cutting off her penis. If she chooses not to do that she's still a transwoman.