"upon this rock I will build My church"...the Catholic church!!
You may wish to check any Greek lexicon. There is no such word as "church" including the word from Matt. 16:18 you quote. This word, most often translated "church", is εκκλησιαν. If you check the definition it simply means "assembly" or "gathering". Unfortunately, the Roman Catholic Organization needs to have an identity brand and created the English word "church" from a Scottish word "kirk". Of course your English Bible renders it "church", to keep the traditionalists away from the publisher's door.
But, notice (if you have any interest in the truth) that the very same word is used for the "riotous mob" in Ephesus (Acts 19:32). In the case of Rome, this may not be too far off the mark, either.