According to the myth in Genesis, Adam and Eve only knew "Good" and not wrong. So therefore since they were told by a snake in a tree (I'm sure he was the top of his class at Harvard) that it was ok to eat of it, why should they not believe it? So I would say yes, they sinned out of ignorance.
I believe they sinned out of greed and arrogance. The snake tempted them, but they had free will and displayed arrogance by ignoring God's directive, and greed by wanting more than God told them they needed
They were warned by God ahead before. At Genesis 2:16, 17 it says, “And Jehovah God also laid this command upon the man: ‘From every tree of the garden you may eat to satisfaction. But as for the tree of the knowledge of good and bad you must not eat from it, for in the day you eat from it you will positively die.’”
The decision that they made was a conscious decision. Since they were perfect, it was a deliberate sin.
No, they were not ignorant of what God required of them, nor were they ignorant of the consequences of their deliberate sin. Eve listened to a lowly creature who never gave her anything (unlike her heavenly father), and Adam was a weakling who preferred to keep his wife happy over obedience to his heavenly father.