As I said in another post, you aren't required to accept proof, or to state that you do if you do.
As I said many times, you can make as many assumptions as you want, it doesn't mean they are real. Saying ''therefore something outside the universe made it'' doesn't mean it's true since you have no evidence of it.
Except that such is what the universe shows us all over the place. Nothing in the universe makes itself spontaneously without something else making it. And the "something else" isn't the thing that it makes. This entirely means that something that is not the universe or of the universe made it. Since we don't seem to have a scientific clue about what made the universe other than some science theory, it's something outside the universe, because if it were in the universe, we would have at least a few clues.
Science agrees with that in big bang theory. I don't have to prove it. Science already does. Wanna know more? Research BB. Or hit the religions if you like the "God" idea better.
''Nothing in the universe makes itself spontaneously without something else making it.'' How do you know? Do you know how everything is made in the universe?