Eilidh,
I believe in a young earth because it makes more sense to me than any of the explanations science has came up with.
YEC is utterly unsubstantiated. There isn't a single piece of evidence that supports the biblical 6,000 year timeline. Not one.
Evidence that scuppers the YEC timeline is legion.
Old earth dates ~ 4.5 bya are corroborated by more than one line of evidence.
How on earth can you say YEC "makes more sense" when this is the case?
Mark
There are 10 kinds of people in this world; those that understand binary, & those that don't