If you want to know about the Big Bang theory of the origin of our cosmos, I recommend you go to the library, book store, or Amazon and find a book and read it.
If you are rejecting the Big Bang theory because of religious dogma, then why are you worrying about it.
If you reject it because its only a theory, then just remember, Atomic theory is only a theory, the theory of gravity is only a theory, the germ theory of disease is only a theory, etc. Point being - a scientific theory isn't a mere guess. There is extensive evidence and knowledge that uphold theories. The scientific method is still be best means to gain knowledge of all things natural.
As an atheist, I don't think people of religion are stupid, deranged or whatever. People of religion believe in what they do because they have been indoctrinated to believe their entire lives.