You are in a tough place, but it is good to remember that your parents are trying to do the right thing. They just happen to be wrong. As Daniel said already, "....they want you to be saved. They are indoctrinated in this belief."
If you can remain such a kind person to them, they should probably keep contact with you as you leave that religion as your own adult. Consider reading Steve Hassan's books to know how to deal with them better. COMBATTING CULT MIND CONTROL has been re-released.