Questions about time, space and big bang

When we talk about the big bang, almost every scientist say that it was the event that made everything, incluiding matter, space, time etc. When you ask if there was something before the big bang they say that there was literaly nothing, and time or space did not exist. However I think its impossible to say that time and space had a begining and will have an end. Well if we talk about the space of our universe (everything until the edge of the universe)and the time of our universe then yes they will have an end when the heat death will ocour, because there will be nothing left in our universe. But the real question is, did time and space already existed before the big bang? Well I cant be sure, in fact no one will ever be sure about this but the answer is: yes. Because saying that nothing was there before the big bang is impossible. You may say that before you were born there was nothing because you are made of matter, cells but space itself, time, and the absence of matter always existed and will always exist. There is just no way that they had a begining and will have an end because its like the infinite itself. You may say that before the big bang, just before there was really nothing, but the infinite exists, so there has to be other universes, other things that had a begining. But the cicle itself never had a begining.