This current universe started at the BB, but nobody yet knows what went on before that. Anyways, you're supposed to be trying to prove your god, and whether the BB was the absolute beginning is irrelevant to the matter.
The 2nd Law of Thermodynamics precludes an infinite acting universe. So I don't know what you mean by current universe and you probably don't either. After all you believe in invisible life forces, souls and reincarnation. If the universe is expanding then it must have a beginning. If you follow it backwards in time, then any object must come to a boundary of space time. You cannot continue that history indefinitely. This is still true even if a universe has periods of contraction. It still has to have a beginning if expansion over weights the contraction. Atheists like yourself have been uncomfortable with the idea of a beginning since the work of Friedman which showed that the solutions of Einstein's equation showed that the universe had a beginning. I think it is time you stop denying science.