This is a question that theists like to debate over, and there appears to be no end in sight for the arguments going on. On one side of this silliness, we have the literalist camp, who claim that the Christian Bible (well, most of the different versions, at any rate) are literally true. They claim that God created the universe at Yom Kippur in 4004 BCE. This date was arrived at many centuries ago by a Catholic bishop who apparently had more time on his hands than he knew what to do with.
Ranged against the literalists, we fin the rest of the Christian world (in this instance), who are inclined to accept the findings of the scientific community. As the evidence found in nature indicates, a best estimate for the question of the origin of Earth is about 5 or 6 billion years ago, while the universe itself appeared in a "big bang" somewhere about 12 billion years ago. While those numbers are still pretty much up in the air, it is a fair certainty that Bishop Ussher's stance was hopelessly wrong by several orders of magnitude.
Which brings me to the point of this article. Faced with overwhelming evidence of the stupidity of their stance, what do the Christian literalists say? They tell us most sincerely that God created the universe so that it only looks old! According to these people, all the evidence found in nature by scientists of all the different fields of study was manufactured by God to fool them. The light from galaxies billions of light-years away from Earth is (according to which creationists you talk with) either beams that were created by God already in-transit, or greatly slowed down from an initial velocity of several million miles per second at the time of creation. Dinosaur bones are either artifacts placed by God in the rocks, or they're critters buried in Noah's flood. The nearly complete absence of radioactive isotopes with half-lives shorter than several million years is simply a coincidence to these people. The list goes on.
For the people who like to discount the reliability of evidence, I have a question. What is there to say that the universe wasn't created 10 minutes ago, by an evil demon bent on playing a huge prank on its creations? A sufficiently diligent and powerful creature could create a world big enough to hold you and your current surroundings for a day or so. It could plant in this small place all the documentation needed to support the delusion that you've lived a long and deeply religious life. It could even plant in your newly-created brain all the memories needed to complete the prank.
So, what are you going to do? Now that I've revealed the nature of the prank your demon is playing on you, how will you get out of the trap? Well, first of all, I'd do some thinking about the nature of reality. Maybe you could also take a little time to find out what objectivity is, and study the nature of knowledge - a branch of philosophy known as epistemology. Unfortunately, you don't have much time. The demon created your universe only 10 minutes ago, remember. Now that his little joke has been revealed, I don't think he'll wait much longer before getting to the punch line. For your own peace of mind, I'd advise you to...