How do you become an exorcist at 13 years old?

You don't, most exorcists are priests, which means that they must be at least 25 years of age. Exorcism is dangerous, and even the most holy priests take enormous risks at major exorcisms. If you are interested in exorcisms, get An Exorcist Tells His Story by Fr. Gabriele Amorth, he was the chief exorcist in Rome for decades:An Exorcist Tells His Story by Fr. Gabriele Amorth

http:www.Amazon.com/An-Exorcist-Tells-His-Story/dp/0898707102