"The age of the moon rocks and samples is older than anything on the Earth."
That may be becuase Earth has tectonic plates that are subducting below other plates into the hot mantle and melts the oldest parts of the plate. While at the same time new material is rising and hardening to take its place. After several billion years a lot of the oldest crust has been subducted under.
The moon is very small and cooled quickly after it was formed, so there are no tectonics to 'renew' the surface.
And/Or
Asteriods and comets from the solar system are believed to be older than the Earth. Evidence from dating of asteriods found on top of the Antartic ice. The surface of the moon is covered with these older meteours and space dust. On Earth, however, most meteourites burn up in the Earths atmosphere before it reaches the ground.