Have you ever wondered how old the earth is?

I know they have it pretty much narrowed down to something. 6 billion I think. But what I mean is have you ever pictured the first person to set foot in south america or Australia. People sitting on that big square shaped rock before they cut it up to build the sphinx. Or maybe a T rex tackling and eating a triceratops in your front yard, where there used to be a large waterfall. The large tribes of people who have risen, fell, and erased by history. The untold stories we'll never know but can only picture