Read the sentence in the Greek. Jesus was not establishing an organization. Poor thing, you have been fed this lie so often that now you are stuck with it as if it is the Gospel. Check the Greek word ekklesia and the meaning thereof. Even Augustine affirmed that the profession of Whom Jesus IS was the rock upon which Jesus is building His ekklesia. But dance some more on the head of that lie and see what it results in for your eternal destiny, as you strive to obtain eternal life by working through the institutionalizations of your religion.
Who cares what Greek says???..Jesus wasn't speaking Greek when He said it, He was probably speaking aramaic and Peter knew EXACTLY what He was saying.