In Galatians 4:4 it says when the fullness of time was come. You see God is never early and God cannot be late. Everything that God does is perfect in timing and season. God created all things including time. The Bible tells us at the fullness of time, meaning at the exact moment in time Jesus was to arrive on earth He did. He arrived at the exact time to the exact parents and to the exact place with an exact plan set forth by God.