The 'in the beginning' of Genesis is talking of the beginning of the history of planet Earth, not as in God. Sort of like if I were to write a story about my son - I could start with 'at the start' or 'in the beginning' & go on to tell of his 19months so far but it doesn't take away from the fact that I & my wife existed before he did.

If that makes sence a bit?

There was a Bishop Ussher who wrote a book called 'Annuls of the World' in which he traces the lineage of the human race back about 6 or 7 thousand years ago to Adam (for help on creation vs evolution issues check out www.answersingenesis.org)
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One thing that we must not think is that God created us out of a need that He had - He was an infinitely happy God before He made us, in fact Paul summed it up well in Acts 17:25 when he said not to serve God with human hands asthough he needs anything. God was, is & would be fully fine & happy without us but chose to make us as a display of His greatness, mirroring back to Himself how great He is. (an illustration i've heard is to say that it's no defect if a fountian of fresh water overflows & pours its water around the place bringing life to the dry dirt. It does not need the vegetation & life that may come from it but it shows off the life giving property of water.