According to the Mosaic law, a Hebrew boy was not part of the family until he was circumcised eight days after his birth; only then was he given his name, i.e., his identity as an individual and as a son of Abraham. It is appropriate, therefore, that any celebration of the Holy Family take place after the celebration of the Circumcision and the Holy Name.
But there is a deeper reason as well. Paradoxically, it is only after we have contemplated the various revelations of the Light to both Jew and Gentile that we can appreciate the period of Jesus' life that is shrouded in obscurity. It is because we now know who the boy Jesus truly is that we can understand the importance of His family and the excellence of His so-called hidden life. Like the shepherds of Bethlehem, we now recognize Him as the Messiah for whom the Jews yearned; like the Magi, whose gifts bespoke their convictions, we now recognize Him as a King worthy of gold, as God worthy of frankincense, and as the Suffering Servant to be one day buried with myrrh. And like the Blessed Virgin, who -- as we learn from the Gospel on this feast-- kept all these things in her heart, we are now in a position to appreciate the unique role of His Holy Family in the economy of our salvation.
These texts on the liturgical year are reproduced from the: Holy Trinity Latin Mass Website.