The new creation was growing and gathering strength within the old creation long before it was definitively inaugurated at the beginning of these last days in the Resurrection of Jesus Christ.
It was the power of this new creation that brought forth the patriarch Isaac from Abraham and Sarah, even though Abraham's body was "as good as dead" and Sarah was barren. (Romans 4:19) In them we begin to see the first light of the Resurrection.
That first light of the dawn that will be the Resurrection of Christ on the first day of the new creation is fully revealed in the conception of Mary. Her conception without original sin is a break with the past, a blessed discontinuity with the heritage of selfishness and sin in which we are all born and know all too well. As the Immaculate Conception she is prepared to be the mother of the new human being and the new creation, a creation far more glorious even than that of the first in the state of original blessing. "The gift is not like the trespass." (Romans 5:15)