As a thought experiment, imagine this. Suppose the age of the brane in which we exist is say the age we think that the "traditional" universe has existed. Then suppose that the age of the "full", "real" universe (in which the brane resides) is such that its ratio to the age above is the same as the ratio of the age above to a nano-second. Could this change your thinking about the origin of the "universe"? The secret to where we came from is to realize that the 19 or 20 billion year age of "our" universe is like nothing.