If the Bible says God created the world approximately 4000BC (you can't get that exact date from the Bible, but the careful genealogical records mean it's not too far off), then that gives us a reliable framework by which we can interpret other data.
The speculative date at the top is based on incomplete data, has a faulty assumption underlying it, or is the subject of some other error.
It stands to reason that you don't treat speculative dates as absolutes by which to weigh whether God's word is true. The other way around is the correct method. God's word is the standard by which you evaluate everything else.