Ok, let's assume first that you will actually have a discussion about this. Next, let's assume all of what you said is true. We allow the possibility that some god character started the big bang. What's next? How does this assertion help us learn anything about the universe? What can we learn about anything by saying "some god character caused the big bang."?
Therefore, based on current science it is quite reasonable to believe in the existence of creator God or universe Designer.
Well, that depends. What, exactly, did this creator god create? If you accept current cosmology, and you also posit that this god character created humans, you have to also accept that he sat on his ass for 13.7 billion years doing nothing.
"Why don't you call upon your God to strike me? Oh, I forgot it's because he's fake like Thor, so bite me" -Greydon Square