Without the virgin Mother, without purity and listening (and hearing) - the birth of God (in each of us) cannot take place. We need to "hear" the Word of God, to be able to give birth.
After hearing the Word, a long time is needed to let the child grow - He needs nourishment, which only the Mother can give. This is a long process and can take tens of years.
The main obstacle is how we can be able to purify ourselves to become the virginal Mother.