You appear to be confusing the knowledge of good and evil with knowledge in general.
Adam and Eve had knowledge, but not the knowledge of good and evil as is shown in the following Scriptures.
Genesis 2:15 And the LORD God took the man, and put him into the garden of Eden to dress it and to keep it.
Genesis 2:19 And out of the ground the LORD God formed every beast of the field, and every fowl of the air; and brought them unto Adam to see what he would call them: and whatsoever Adam called every living creature, that was the name thereof.
Genesis 2:20 And Adam gave names to all cattle, and to the fowl of the air, and to every beast of the field; but for Adam there was not found an help meet for him.
Genesis 2:23 And Adam said, This is now bone of my bones, and flesh of my flesh: she shall be called Woman, because she was taken out of Man.
Genesis 3:2 And the woman said unto the serpent, We may eat of the fruit of the trees of the garden:
Genesis3:3 But of the fruit of the tree which is in the midst of the garden, God hath said, Ye shall not eat of it, neither shall ye touch it, lest ye die.
Man had to have an instinctive knowledge of how to dress and care for the Garden, when God placed him there.
Both Adam and Eve had the intelligence of recall else they would not have remembered that God had commanded them not to eat, which shows a basic knowledge of understanding.
Hope this helps
These Scriptures not only show that man instinctively had knowledge prior to the fall, but also had the power of reasoning, as is demonstrated by his being able to discern the differences between animals, and devise names for them, and also to reason that Eve should be called woman since she was taken from man.
And although we are not told how man got the concept of death it is obvious that he did have and could reason that if he did eat of the tree of the knowledge of good and evil that he would die.
The knowledge of good and evil then boils down to what was acceptable behavior to God and what was not acceptable. In other words they would not have known that lusting for the opposite sex was sinful as is evidenced by:
Genesis 2:25 And they were both naked, the man and his wife, and were not ashamed.
God had already given them the command to replenish the Earth so they were aware of sex, but until they gained the knowledge of good and evil they did not have any reason to associate any wrong with it.
If we analyze the knowledge of good and evil, what we come up with is that it is really pride, by this meant that it is pitting man's desires against God's desires. Therefore choosing man's desires over God's desires is sin. So let me give that some clarification.
Genesis 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.
From this Scripture two things become apparent;
- The key to Eve's sin is in the to be desired to make one wise, part in that Eve was not content with how God had created her and desired to be more wise, that would then give her the ability to use her free will to bolster her pride.
this is more apparent when we consider:
Genesis 3:5 For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil.
- Adam was not deceived and willfully chose to eat, whether his pride caused him to desire to be equal to God in knowledge, or from not wanting Eve to be more knowledgeable than him.
In both cases it is pride which causes them to sin in the beginning. It is worth noting at this time that their sin was in disobeying God's command, and not just having the knowledge of good and evil. From my studies ogf Scripture it is pride which God detests the most in man.