A really hard question on Satan and deception.

[Godscreated]

They knew the difference between what was right and wrong, God told them not to eat of the tree or there would be consequences (death) to disobeying God.

Wrong! Gotta actually read the bible to play in our yard.

Adam and Eve had not yet ate from the tree of knowledge so they did not know right from wrong and they had not yet ate from the tree of life so they were going to die anyway.

And the LORD God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever:

Surely you can't be serious, the only way you can read that into scripture is with blinders on.
NAS Gen.2:16-17 And the LORD God commanded the man, saying, "From any tree of the garden you may eat freely; but from the tree of the knowledge of good and evil you shall not eat from it, for in the day you eat from it you shall surely die.
Gen.3:2-3 And the woman said to the serpent, "From the fruit of the trees of the garden we may eat; but from the fruit of the tree which is in the middle of the garden, God has said, 'You shall not eat from it or touch it, lest you die.' "

Both these passages show that they had been told not to eat the fruit or they would die. They ate and lost their pure spiritual lives and they also had death come into their lives. This is why God would not allow them to eat from the tree of life, they would have had an eternal life that was sin filled and what a miserable life that would have been, God granted them His grace by not allowing them to eat of the tree of life. Actually this is the hell that nonbelievers will live, eternity in sin and misery. Eve demonstrates that they knew it was wrong to eat from the tree of good and evil. Adam and Eve died a spiritual death when they ate the fruit and then later in life would physically die. I do not know how many times scripture tells us that spiritual death is separation from God but it's many times, and because God can not be in the presence of sin, we've become separated from Him because of Adam and Eve's disobedience. This is simple why can you not understand it. This i the reason that Christ came and redeemed us through His death and resurrection.