"believers say God did it; scientists don't"
That implies if you are a scientist then you can not also be a believer in one of the religions, which is demonstrably untrue. One can study science and hold the view that it is only giving information about one aspect of reality.
The concepts are difficult to get to grips with. First it is thought that time only starts when there is space and matter, so there would be no time before the big bang. Unless of course you believe in an oscillating universe that contracts then expands again.
And what of the thought that event s in an existing universe can create others ? In the new universe time has just started, but in the universe that kicked them off, time has been running for quite a while.
But this doesn't really explain why such things as the uncertainty principle exists to kick a universe off in the first place. Even if time started for that universe as it came into existence what causes the maths to exist to allow it ?
I think it is reasonable to believe there must be a first cause for it all, and one is entitled to consider this cause 'God' if they wish. But at least part of the way back is the idea that you can not apply cause & effect to the quantum domain so trying & failing to avoid references to time and position, it is inevitable the at some point something comes into existence, no matter how long the odds against it., and then all you need is for that to trigger a big bang type scenario.