If time stops before our historical graph can reach it, why does anyone believe that the universe was ever in that one-dimensional state to begin with? The very notions of 'state', and 'beginning', cannot be applied to something that must be outside of time and space. People think about the 'big bang' and wonder, "where did all the energy for such an incredible explosion come from?" But their question is misguided, because by definition the energy could not come from anywhere, and furthermore, the explosion would be creating space as it goes along, which contradicts our concept of an 'explosion' anyway.
I don't think there ever was a 'big bang'. I think the passage of time becomes infinitely slow on our cosmic graph, just as space becomes infinitely small. Going back in time, approaching the 'big bang', would be just like tumbling into the grasp of a black hole. You would never reach your destination.