I am going to share my personal thoughts on the subject, and examples from Scripture of how God has used the teen years to make an impact for His kingdom.
I backed up to get the context. Peter and John had just healed the lame man, who, by the way, was older than forty (Acts 4:22) in the name of Jesus. Peter began to speak about the things concerning Jesus, with boldness. A crowd gathered and the authorities were aroused because of the ordeal. The religious leaders were furious that Peter and John spoke out about the saving power of Jesus