Matthew 26:33-36, "Peter said to him, “If they all fall away because of you, I will never fall away!” Jesus said to him, “I tell you the truth, on this night, before the rooster crows, you will deny me three times.” Peter said to him, “Even if I must die with you, I will never deny you.” And all the disciples said the same thing."
I'm not sure what the connection is between Peter becoming "the first Pope" and the verse that you cite, which is part of Peter's fantasy about how devoted he was to Christ.
The so-called "first Pope" was called Satan by Jesus
Matthew 16:23, "But he turned and said to Peter, “Get behind me, Satan! You are a stumbling block to me, because you are not setting your mind on God’s interests, but on man’s.”
As we all know, Peter was wrong about his loyalty to Jesus. He denied knowing Him three times in one night! In Matthew 26, it says, "Peter said to him, “If they all fall away because of you, I will never fall away!” Jesus said to him, “I tell you the truth, on this night, before the rooster crows, you will deny me three times.” Peter said to him, “Even if I must die with you, I will never deny you.” And all the disciples said the same thing."