Hello,
If Adam and Eve had no knowledge of the law of God until after they had sinned it could not rightfully be called sin then could it? Heres why:
"...For sin is the trangression of the law" 1 John 3:4
"...for the law is the knowledge of sin" Rom 3:20
"...He that committeth sin, is of the devil, for the devil sinneth from the beginning" 1 John 3:8
That is why children have the age of accountablity, because they are unable to comprehend the full extent of the law within their immature intellects. However, Adam and Eve weren't created children, they were made fully mature adults, able to comprehend the difference between right and wrong, they did understand God's law, as God freely walked and talked with them prior the fall, why do you think the serpent was "subtle" in his temptation?, he had to "beguile" Eve, as she did have a full understanding of God's law. She may not have grasped the full consequences of transgressing that law, but she knew it. Just think of how many commandments Eve broke when she ate that fruit.
If the devil sinned "from the beginning", and one requires a knowledge of the law to sin, then logically,there must have been a knowledge of the law from the beginning for sin to have occurred.
God bless,
Harlin