The apostles were "those who are sent".  That includes all of them and all of us.  The Twelve were chosen to (eventually) judge the Twelve Tribes of Israel.  They were not ordained as priests.  The Jewish priesthood was quite active during Jesus' time and His words directed to them were not flattering.  Jesus Himself was a layman Who chose only laypeople as His first followers.  The hierarchical, doctrine-spouting institutional church doesn't look much like the earliest Christian communities.  Unfortunately.