When I was a teenager, I wanted to drive a stick shift. I had a friend who drove a five speed and I thought it was neat watching her push the clutch in, switch gears, let off the clutch and still maintain speed. I begged her to let me drive it one day. I jerked the car into first gear, didn't do the pedals right and the car went dead on the road. Even though I had watched her drive it numerous times, I wasn't as ready to drive a stick shift as I thought I was!
Simon, would later be given the name Peter, could relate. After eating supper with Jesus and the disciples, Jesus told them he would be betrayed. Peter responded in Matthew 26:35, "'Even if I have to die with you, I will never disown you.' And all the other disciples said the same."
Peter was genuine about what he said! He was basically saying, "Jesus, I'm ready to do whatever you want me to do. I am on board with whatever that is!" And notice the rest of the disciples chimed in saying, "Me, too!" But Peter wasn't ready to move on to what God had for him next, even though he thought he could handle it.
Simon meant "to hear". Peter meant "rock". The distance between Simon and Peter was spiritual growth. That growth pattern included quite a bit of hearing or listening to God. You can read 1 & 2 Peter and see the growth that Peter had between his two names. He wasn't the same person whom Jesus initially met as a fisherman. After much growth in wisdom, faith, and some hardships, Peter became the rock Jesus said he would be and was ultimately the leader of the early Christian church in Jerusalem.
Spiritual growth happened all through the Bible. There was spiritual growth between Abram and Abraham; Sarai and Sarah; Jacob and Israel; Saul and Paul. They weren't the same people they started out being. Their testimony was different when they came into their maturity.
Although you and I may feel like telling God, "I can handle this. I know what I'm supposed to do. I'm ready for the next step," be patient in letting the Holy Spirit develop in you before you get ahead of God's will for your life.