The Word functions as the act of existence of the human nature of Jesus Christ.
Yes. The human nature of Jesus Christ began to exist in time, in the womb of Mary.
If you deny that Jesus Christ, the man who was born of Mary and lived in Nazareth, is God, the Second Person of the Trinity, then you are not a Christian, but have invented a new religion for yourself.
If you deny that Mary, an unknown Jewish girl until an ANGEL visited her, added MORE than FLESH to the Second part of the Trinity (which pre-existed her by ETERNITY), then you are a CATHOLIC, and have accepted a different gospel.