Aww sweetie my prayers go out to you.
It is always hard when telling someone you care about your inner most feelings and wishes but I just want to tell you that you don't have to say anything until your totally ready with it. Not everyone is tolerant of other peoples paths and some people are, its what we all have to come across in life.
I think before you tell him you should truly come to terms yourself with what faith you are and even though every ones path grows in time the fundamentals of it usually stay the same.
When you've done that you could compile a folder of some sort of research on it detailing what it is you've chosen so you can show him exactly what your about.
Most in toleration comes from ignorance. If you show him exactly what your about with facts etc. it might help stamp out some myths about witchcraft he has, helping your course.
Catholics believe we are helping the Devil with his work but if you show him your path is different then that should help you.
Lastly really try to enthesis your still the same person and nothings changed, most parents fear change in their children more then anything. Bless them.
I really hope that helps...
? What if he thinks i'm a freak? What if he tells one of his buddies and they tell their kid or something and the people at my school find out (though unlikely, but then again, my town is small and everyone is gossip freaks)? Not in a self-centered way, I'll admit that i'm a very strong and just person, but there's only so much cold shoulder and insults a Witch can take.