4DC,
I think you did the right thing for your friend, especially since she is a very close friend of yours and it appears (from your post) that she's living a double life. You have given her the opportunity to be free. Although, a lot is lost when communicate via email, if someone is not on good terms with you they will read an email from you before they actually speak to you. So sometimes, email is the only channel for communication.
When you learn the truth about the JW religion, you really do want to shout it from the rooftops and you wonder why every newschannel and magazine is not doing a expose on all the lies behind the organization. Also its very hard and very draining "to pretend" you don't know what you know about the org with your close friends and family. If you have absolutely no plans of going back...I think you absolutely did the right thing. But I would not recommend the same course of action for anyone that is extremely active in the org.
Since you already put it out there...no need to worry...like someone else said just let the chips fall where they may. Be thankful that you got out at such a young age, it took some of us years to figure this thing out.