According to Genesis God made everything in only 6 days time. Creationists use this information to proof that the world is only 6000 or maybe 7000 years old, since that is how long there are humans (most likely)
Somewhere else in the Bible it says that what is one day to us, can be 1000 years to God. God is not bound by time so the author of that particular part could have said 10.000 years or a million years, or 10 seconds as well.
If we now combine these 2 bits of information we see that God used 6 days to create the world, the universe, everything, but that we do not have a clue how long those days actually were in Earth-time.
Let me know if I am wrong there, because if I am not, then I do not see why the Earth should be only 6000 years old.
Hoping for some answers.