There are levels and levels of imagination, as your dreams and visions prove. This world is sustained by Divine Imagining, which is human imagining on a higher level. Our imagination is keyed low, but we are called upon to exercise this power, to examine ourselves to see if we are keeping our faith.
When you give yourself completely over to the gospel story you are ready, and God will assume the mask of the one who is expressing it at the moment. Then you will have union with that being and bear the child.