A few posts ago I mentioned that we get to "The Fall" too abruptly in our renditions of the biblical story. It seems absurd, but it may be that we get to "Creation" too quickly also.
It's an absurd thing to claim, because the first verb used in the Bible is "create", and it is a word that pops up repeatedly throughout the Bible's opening chapter. But for Chrisitians, the is another Word that comes before any word in Scripture.
Judaism developed this kind of thought into its worldview, with personified Wisdom seen to be in existence before the worlds were created. For the emerging Christians of first-century Palestine, Christ became that Wisdom.
If there is an answer to the question "why?", it is not found in Genesis but in passages like Colossians 1:15-20. Creation was created for Christ. We are, in Triniarian thought that is completely alien to the original meaning of Genesis 1-2 but nonetheless valid, the Father's gift to the Son.
But there is more. Lest we think of ourselves as simply objects in a divine show of affection, we who are a gift have also received a gift - "For God so loved the world, that he gave his unique Son..." The same love that the Father has for the Son he also has for the world. The Son received the world, the world received the Son.
When Christ is placed at the beginning, what is traditionally the first act of the biblical narrative -- creation -- can be properly understood. Not only are we objects created for the good pleasure of God, but we are subjects to be known by God, as he is a subject to be known by us. Though there are vast distinctions between Creator and creation, there is a mutuality that can't be ignored, especially when our beginnings are founded upon the Word who would become flesh and dwell amongst us.