Well, you know one now. I rejected Catholicism at age 13. As an adult, I started going to a Bible-preaching Evangelical church.
You prove my other point made in this thread. No 13 year old from a practicing Catholic family would permit a child to make such a decision. When a very young teen rejects his faith (any faith), I can only assume he experienced very little spiritual guidance or training at home. Perhaps your parents were divorced. Often, that's when parents lose their faith, neglect religious training, and begin to set a poor example.