I'm just being what any truly rational person should be, looking at the facts and choosing the best explanation for all those facts. That's how any scientific hypotheses works. But you still don't want to believe in God. You are simply not being a rational person with any of the facts that we have. You just don't want to believe it, not for intellectual reasons, but because you just don't want do believe it period, with no evidence on your side.
All science is built on the principle of causality.
Since something cannot come from nothing, something has to be eternal. It's either God or the World. In 1929 a man named Edward Hubble discovered that the redness of the stars showed that the universe was constantly expanding equilaterally in all directions. He said that the best explanation for that is that there must have been a point in time, called the Big Bang theory where the universe was nothing and then came to be. To further the evidence for the universe having a beginning, there is the scientific law, the 2nd law of Thermodynamics.