Eph 1:4 According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love...
I believe that God planned and ordained a way of salvation before He laid one brick, so to speak, of this world in His creation. Salvation was not a last minute plan as a lot of nail biting went on in the heavenly regions during the events of Genesis 3. No, I believe that salvation was always a part of God's plan. 1 Peter 1:20 in talking about Christ states..."who was foreknown indeed before the foundation of the world, but was manifested at the end of times for your sake..." (ASV) Adam Clarke comments on this scripture, "...it shows that God, foreseeing the fall and ruin of man, appointed the remedy that was to cure the disease."
Consider the implications of this foreplanning. Did God plan for His creation to sin? No. But, God is sovereign, all knowing and knew what would happen if He created humankind with a free will. He knew all of the events of what would happen if He created us.
Now this is hard for us to understand. Why would God create humans if He knew they would rebel against Him? That is a question I can't answer. But, I can say that God wanted a relationship with us, the crown of His creation. He wants me to choose to love Him. He wants me to desire Him more than anything. But, He always leaves the choice up to me...and you. He is a gentleman...He will not force Himself on us.
In Genesis 3, the Savior is foretold as soon as the first sin occurred! Genesis 3:14-15..."And Jehovah God said unto the serpent, Because thou hast done this, cursed art thou above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life: and I will put enmity between thee and the woman, and between thy seed and her seed: he shall bruise thy head, and thou shalt bruise his heel." (ASV) This is an amazing prophecy concerning Christ! Praise the Lord that the remedy was already in place!