I feel like im losing my best friend

I was always wary that J was converting for the wrong reasons. That subconsciously it is for N and N only. I know he isn't pressuring her in any way and that all the choices she is making are her own but I feel like she is changing so much and it scares me to death. No drinking, no parties, no hugging boys and not even telling me what's going on with her a N. Her blind and unwavering devotion to a god she only discovered 3 months ago? I don't want to lose her. I can't.