This is a question we need to be able to answer in such a way that the world can understand. We must not cave in to those who would say that the universe is millions of years old. If we cave, we also say that death comes before sin. If we accept that, we have a huge theological problem on our hands. Additionally, the straightforward reading of Genesis 1-2 indicates a six 24-hour day creation. When we read other interpretations into Genesis 1-2, we are in effect saying that scripture does not mean what it appears to say. What can we then say about the life, death, and resurrection of Jesus?
When you have about an hour, take the time to listen to Dr. Mohler. It will be worth it.