Yeah, I agree with you. They big bang couldn't of been the origin of everything. What some scientists are saying now is that what most likely is out there are multiple universes in a sea of them- outside of ours. The 'Big Bang' was just the branes, or outer walls colliding making our universe. As this might be the case, still who could of made the origins of all these different universes. But I don't think we can denounce the big bang didn't happen yet, what if God used this? We don't know, but we just have to trust him.
As you may know, the origin of all the different molecules we see and use and made by stars. Nuclear fusion, combining parts of H2 atom to make different elements. But how these molecules combine to form life is something I just can't grasp, I also can't grasp how other people assume life just happened. Sometimes I wish science could prove God right but that's what keeps us bound.