The first sin. Misconception is that Eve was the first to sin when that’s not really all that true.
You see
When God created everything and then Adam. He told him about the tree he said don’t eat of it.
God never told Eve.
When Eve was in the garden being tempted read that section you’ll find something interesting. Adam was right next to her and he didn’t say anything. He was using Eve as a Guinea pig.
Eve bit into the fruit nothing changed she handed it to Adam. And when he bit into it their eyes were opened.
So really the first sin was Man’s passive nature allowing something to happen he was told not to allow happen if he never ate their eyes may never have been opened but who knows.