Why the shepherds?

Why did God choose the shepherds to be announced first after the birth of Christ, to be the first to see the glory of God displayed after 600 years of silence, to be the first to see the sky erupt with an army of angels worshiping God, to be the first to see baby Jesus in the flesh on the same night he was born and the first ones to proclaim the gospel? Why were these smelly outcast, lowest of the low, sinful shepherds chosen?