The age of the earth doesn’t necessarily prove or disprove Darwin, just as Darwin’s theory of evolution doesn’t necessarily prove or disprove the existence of God.
If the earth is young, it absolutely falsifies darwood’s atheist creation myth, because it requires vast ages of deep-time to be even remotely plausible. Although, now that I mention it, not even trillions upon trillions of years would be enough time, as Dr. Pitmann ably demontrates here:
http://www.detectingdesign.com/flagellum.html#Calculation