I will leave you this.That makes no sense given Simon is continued to be called Cephas...
Furthermore, given your interpretation, our Blessed Lord would've said, "You are likened to a rock..." Instead, he says, "You ARE Peter..."
Mat 16:18 And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.
Jesus used Caesarea Philippi to show that evil which the Disciples saw with their own eyes that of what they would come up against being the gates of hell found on that literal large rock. Jesus was confirming Peter's confession preparing them before they were sent out into the world as the gates of hell can not prevail against Gods true Church being the body of Christ with He being the head of the body. It was Paul that first established the Church in Philippi, Acts 16:10. It's faith that builds the church like that of Peter's confession of who Jesus is.