I want to leave the org but have no idea how to tell my mother(who is a faithful jw).
I haven't taken time to read all the replies yet, but I'm hopeful that others also said: DO NOT RUSH IT!
Proceed slowly and cautiously.
Your age and personal circumstances will make a huge difference on how to proceed. Since you ID says "teen", I suspect you probably still live at home and may even still be in school. If that is true, the most important thing you can do is apply yourself in school and get a good basic education that will allow you to go on to college/university.
If you're going to be successful in this life, it takes a good education and planning.
The greatest revenge is living a happy and successful life!
Good luck,
Doc