time line reflection

One of the major events in earths history was the first land plant, this was very important because is showed the first signs of life on land. A second major event in earth's history was the time of the dinosaurs, this was very important because it was  a time of massive biodiversity. Another major even was the ice age, this was important because this was when the world was covered in ice. the scale of earth history is bigger than the planet itself, and what real surprised me was how old the world is. To me its mind blowing that the amount of time we have been on earth is century's compared to use, but it is only a small fraction of the earth history. I only have one question"Why was the Earth made in the first place?"