Questioning Singularity and Time, Null Universe and Conservation of Universe

The Big Bang Theory is one of the most trusted theories for the formation of the Universe, and in the progression of the theory we forgot to ask the question “How can something exist in nothing?” Singularity which we all know is nothing but a dense curvature whereas occupies nothing space. But it does require Space although a little but it does, so before Big Bang, there was no space and no matter, then where Singularity has existed. And if there was no time before the Big Bang then was time determined inside the Singularity at that time, because singularity exploded and thermodynamics lays rules that entropy increases with time, so did time exist before Bang? We can’t answer that question with mathematics but with modern physics, also physics doesn’t allow us to trace the space-time before the big bang, then how can we answer that question.