I can only speculate as to how old the earth is. As your friend at work said, science says that it's been around for billions of years. The actual age of the universe, according to science, is probably around 15 billion years.

The question you are probably asking is this: What does the Bible say? Maybe you were taught that according to the Bible, the earth is only a few thousand years old.

Actually, the Bible doesn't say that. Some guy by the name of Bishop Ussher said the earth began in 4004 B.C. He calculated the genealogies in the Bible and counted backwards to Genesis 1:1.