As you can see, Simon was already known as 'Peter'
NIV Matthew 4:18-19
18. As Jesus was walking beside the Sea of Galilee, he saw two brothers, Simon called Peter and his brother Andrew. They were casting a net into the lake, for they were fishermen.
19. "Come, follow me," Jesus said, "and I will make you fishers of men."NIV Matthew 8:14
When Jesus came into Peter's house, he saw Peter's mother-in-law lying in bed with a fever.NIV Matthew 10:1-2
1. He called his twelve disciples to him and gave them authority to drive out evil spirits and to heal every disease and sickness.
2. These are the names of the twelve apostles: first, Simon (who is called Peter) and his brother Andrew; James son of Zebedee, and his brother John;NIV Matthew 14:28-31
28. "Lord, if it's you," Peter replied, "tell me to come to you on the water."
29. "Come," he said. Then Peter got down out of the boat, walked on the water and came toward Jesus.
30. But when he saw the wind, he was afraid and, beginning to sink, cried out, "Lord, save me!"
31. Immediately Jesus reached out his hand and caught him. "You of little faith," he said, "why did you doubt?"NIV Matthew 15:13-16
13. He replied, "Every plant that my heavenly Father has not planted will be pulled up by the roots.
14. Leave them; they are blind guides. If a blind man leads a blind man, both will fall into a pit."
15. Peter said, "Explain the parable to us."
16. "Are you still so dull?" Jesus asked them.
Yes, He did!
Elsie, You do realize that those references to Peter were written years after the events described, right? Therefore, Simon was not ALREADY called Peter when those events unfolded. He was called Peter later and was known as Peter when the events were written about.