Ricktheheretic
"Do what thou will shall be the whole of the law"
No, there does NOT have to be a time before the BB, nor even a time *of* the BB. In fact, that is part of what the term 'singularity' means in this context: that even defining time at or before is impossible: the time coordinate simply cannot be extended backwards further.
A good analogy is latitude on the Earth. It cannot be extended to either north of the North Pole nor to south of the South Pole. The reason is the geometry of the sphere of the Earth. In the same way, spacetime has a four dimensional geometry where (at least in general relativity), the time cannot be extended backwards from or even to the singularity.
The conservation of matter (the correct version is actually the conservation of energy, because matter can be converted into energy) actually says that the total amount at one time is the same as the total amount at any other time. In other words, it compares the amount at two different times. If there is no time, there is nothing to compare.
So you are saying that something can come from nothing? That doesn't make sense. I'll read the Big Bang theory and the Atsro-Physics book, but I don't think it logically makes sense that there was nothing and then there was something. What would it's cause be? To me "matter cannot be created or destroyed" makes sense because nothing cannot make something and something cannot become nothing. What exists is, and what does not exist isn't unless it comes in the future from what already exists. That's just my take on the subject