Richie, thanks for the really good post. I'm sorry to say the guilt trips are not going to end when you turn 18. I am 30, and I get into a similar conversation almost every few days with my mother. She relentlessly tries to equate her worth and her parenting skills with my feelings toward the organization. So anything I say, any good point I make, she responds with an apology for "not being the kind of mother I wanted" or "doing her best and giving everything she had for me".
It is awful to deal with. A couple days ago I asked her a question: "Would you rather see me happy and healthy, or would you prefer to see me at meetings, even if I am miserable and suffering?"
She responded, "I would rather prove Satan a liar."
WTF? It can be overwhelming. I don't know exactly what will ever help this situation, but I have decided to follow the same course I am following with my wife (good advice I got here on JWD): I will prove that I am there for her, spend extra time with her, and reassure her of my love in ways that are completely unrelated to religion.
After that nasty conversation, I called her back and told her this. "I love you and I would do anything for you. How I feel about religion has nothing to do with how I feel about you, and that will never change. As long as it depends on me, I never want to lose contact with you guys."
Good luck to you, my man.