First WELCOME!
You are doing the right thing by leaving the JW's. I honestly and thoroughly believe this. It's going to be hard. Many of us have gone through and may still be going through the same emotions and fear that you are feeling at this time. But with support from groups like this and the courage to stand up for what we now know is right and true...you can make it even in the face of opposition from your mom & grandma & other assorted family & friends.
My mom & my sister shun me because I chose to leave this CULT. I used to think that I couldn't endure anything like that. But what I really couldn't endure was compromising my new found principles of what is right and wrong, and the JW's are just down right wrong! The pain and misery that they have caused to countless people is evil and unChristian. (Shunning, tolerating child abuse, allowing the murder of innocent people in Malawi, etc, etc, etc.) Stay true to your gut feelings.
I raised two kids in the JW's. I only wish now that I could turn back the hands of time and raise them to be happy, healthy INDIVIDUALS's without all the Watchtower garbage clouding their minds.
Hang in there...things DO get better. I would highly recommend reading Ray Franz's books...Crisis of Conscience and In Search of Christian Freedom. That's going to give you the information you need to know that you are making the right decision by leaving the JW's and not looking back. Have that birthday party for your son and enjoy it in good conscience!
Cathy L.