You are not getting it, Gen 3:6 shows Eve had sinful desires before she actually sinned.
Gen 3:6 And when the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat.
Scripture says she was tempted and gave into the temptation. Therefore sin was not imputed unto Eve but unto Adam. Adam was not tempted. Adam rebelled against directly against the command of God.
Adam didn't need a sin nature to sin. Neither do we. That will be evident in the Millennial Kingdom when some without a sin nature will rebel against Christ.
But as for now we sin because: we are sinners, and because we like to sin. Both are true.
[quote[We have a detailed description of Eve's temptation here. She had the lust of the flesh, she wanted the forbidden fruit because it was good for food, it would satisfy her fleshy appetite and hunger. It was pleasant to the eyes, it appealed to our fleshly desire for beauty. It was desired to make one wise, this is the pride of life, we all desire to be intelligent and wise and take great pride in this.[/quote]
So Satan said. He convinced her of all that. He convinced her that that which appealed to her senses was greater than God could ever offer her, and she gave into that. She believed Satan more than she believed the promises of God. Perhaps she was trusting her emotions.
Eve had these desires BEFORE she sinned.
That is part of the image of God. Emotions are natural. We wouldn't be able to love one another without a certain amount of love.
We are no different from Eve, we have this same nature.
No we don't. We are under a curse. We were not created innocent. There is no such thing as innocence in this world. Each and every one of us is born with a sin nature. We are sinners at birth by nature, the children of wrath, as Paul states it.