This view, taken from a literal interpretation of the first few chapters of Genesis, and which states that God created the Earth in six literal days and no more than 6,000 years ago, is called Young Earth Creationism. This is the position, I believe, of many churches, and is the reason for the supposed conflict between Christianity and the theory of evolution. Personally, I grew up with this view, and never thought anything could change my mind. However, since entering college I've come to realize that one can very well be a true believer and also believe in the theory of evolution and its implications, such as the old age of Earth. And even if these things aren't true, to say that God could not have used the theory of evolution to create what we have now is, I believe, a sin; it limits God. I did not say that it's a sin to believe either of these views, but to say that God was and is incapable of using evolutionary theory--or of creating the world in six days with nothing different then from what we have today--to say that He was and is incapable of it is, I believe, wrong. These are, as you probably know, very controversial issues. Although we should try and find out what is true---indeed, Christians should be the leaders in investigating for truth---we also need to keep these things in perspective. When Christ Jesus comes again, will believing in Young Earth Creationism save us? Will believing in evolutionary theory? No---only God's grace and our belief that our salvation was effected in Christ's death and resurrection will save us.
For more information on these subjects, I recommend Francis Collins' The Language of God. Collins is a Christian geneticist who was the head of the Human Genome Project. I found him very helpful, because he explained confusing and complex scientific concepts in everyday language, with few exceptions.
Hope I've helped!