Hi gttm, I was never a JW so all I know is what I read. I scanned a little of your posting history.
I'm sure you already know more then me about the org. besides JWFACT etc but here is a modest suggestion.
It's a religious approach. Just so you know, I am a christian, not much of one but that another story.
All Christians believe the gist of Genesis 3 is what got us in trouble so have her rehearse the story.
Ask if Adam / Eve could enter/ renter the "Earthly Paradise" as sinners.
Ask her if she is a sinner equal to Adam. How can any sin enter the Earthly Paradise?
Well you found these on JW.ORG
*** w74 2/1 p. 96 Questions From Readers ***
Jehovah God, on the basis of his Son’s sacrifice, “declares them righteous” and thus views them as being perfect, without sin, while yet in the flesh on earth
*** w72 9/1 p. 518 A Death That Brings Gain ***At their death they likewise do not die as sinners
Obviously she will say that only for the anointed but what if we are all still equal to Adam just like the org. says.There is a way for a sinner to not be a sinner and enter paradise, just saying.