Why do you think the angels appeared only to the shepherds when Jesus was born, and not to a vast number of people? Didn't God want people to know that Jesus had come into the world? — M.McD.
God certainly wants every person on earth to know that Jesus Christ came into the world -- and not only that He came, but also that He died for their sins and rose again to give them eternal life.
But when Jesus was born, it was only the first step in God's plan of salvation. From all eternity, God had planned to redeem the human race from its slavery to sin -- and now on that first Christmas the process was beginning! In reality, God had already been preparing the way -- but now He was taking on human flesh and becoming a man so that we could be saved. In time, that process would be completed through Jesus' death and resurrection -- but at first His plan was almost invisible.
There was, however, another reason why Jesus' birth was announced first to the shepherds. They were humble men; in fact, shepherds were looked down upon by many people. But Jesus Christ came for all people -- rich and poor, male and female, uneducated and educated. By announcing Jesus' birth to the shepherds, God was demonstrating His love for every one of us, no matter who we are. The Bible says, "How great is the love the Father has lavished on us, that we should be called children of God! And that is what we are!" (1 John 3:1).
What if you had been present that first Christmas night? Would you have ignored Jesus -- as most did? Or would you have joined the shepherds in welcoming God's Son into the world -- and into your heart?