It took 4.6 billion years for the earth to become hospitable for life.  When humanity finally evolved to the point when they could be called 'homo sapiens'---there were more than just a single couple living.  There was NEVER a time when there was a perfect garden paradise, or talking animals.  

God so loved the world, that he wanted to become PART of this world and the humanity that people it.  That is why Jesus came in time, "to pitch his tent among us."  We had developed enough to understand that we can cooperate with God---to bring about 'God's will and God's kingdom of peace, love and blessing to all of creation---to our brothers and sisters.  Jesus shared in our human nature, which God created as good.  Jesus brought blessing to us from his Incarnation.  There was NO ORIGINAL SIN.  God loves us so much that God "became man and dwelt among us."