You must also believe in Santa Claus, the Easter Bunny, and the Tooth Fairy. Anyone who thinks the world is much older than 6000 years is living in fantasyland with fairies and trolls.
Actually I don't believe in any of those. I used to, when I was a kid. Before I became educated.
I used to believe Bible stories as well. But again, that was before I became educated. Before I learned that facts and evidence have value.