Why do you even need to 'otherise' yourself like that? The alternative of a trans woman is a woman. The alternative of a trans man is a man.
There is no 'cis' needed.
Is there a reason why you need to qualify yourself?
Why can't you say you are a woman? That is, after all, the default position. You give a clue what it's about when you state that women can't just be women. If trans people have to have a prefix, then therefore WOMEN are the ones who have to give up their term and add a prefix.
See that there, is the problem. Everything is changed just for transgenders. You cannot allow us just to be.....women. You have to erase or change that and add a prefix to it.
If you can't see how unfair and wrong that is, I don't know what to say to you. But cisgender is deeply offensive to women, for the EXACT REASON you have outed it. That if person who was born male can't be a woman, then NO ONE is allowed to be, without us adding a prefix. It's stamping their feet 'if we can't be just women, then THEY can't either!'
You have unwittingly demonstrated that the goal is to erase women. To remove our status, just to suit another group. You don't realise it, but you outed your goal. The erasure of 'women' as a category.
I am not a 'cis'. I am WOMAN (*and hear me ROAR!). I am the default. And I don't need a qualification nor a prefix added just because a person born with male genitals wants to be a woman.
I say to you, what is wrong with just......woman?
In deference to our recently deceased great Australian singer (and hell would boil over if you suggest to our National Hero that she change her title to 'cis woman'),
^I am woman, hear me roar
In numbers too big to ignore
And I know too much to go back an' pretend
'Cause I've heard it all before
And I've been down there on the floor
No one's ever gonna keep me down again
Oh yes I am wise
But it's wisdom born of pain
Yes, I've paid the price
But look how much I gained
If I have to, I can do anything
I am strong (strong)
I am invincible (invincible)
I am woman
You can bend but never break me
'Cause it only serves to make me
More determined to achieve my final goal
And I come back even stronger
Not a novice any longer
'Cause you've deepened the conviction in my soul
Oh yes I am wise
But it's wisdom born of pain
Yes, I've paid the price
But look how much I gained
If I have to, I can do anything
I am strong (strong)
I am invincible…^
I....am.......WOMAN!