Show us where it says anywhere in the Bible that the earth is only 6,000 years old.
If you read the Creation account literally, as many do, you have to conclude that the time between Creation and the Incarnation is about 4000 years. Add the 2 millennia that have passed since the Incarnation, and you get 6000. My point is that it isn’t sufficient to just “read the Bible”. We need an authority to guide us. Just as the Jews of the Old Testament had the Patriarchs to guide them, we have our own patriarchs to guide us, namely, the Church.