''It must have had a beginning'' is reasoned from a mind that can't comprehend infinity. Our science having come up with the 'big bang' as an explanation and mathematical starting point is, as far as I'm concerned, a desire to pinpoint a beginning to which we can hold onto. A means to peace our minds, a way to cope, to have ''the world make sense''. And interestingly, very much ''in tune'' with a cultural Christian context.
But does any of this really make any sense? Do you really think you are part of a world that ''makes sense''?
Nature and evolution are so unpredictable and chaotic, I think it is immature to think of the entire universe as some purely save and orderly place.