momzcrazy,
yup, its tough to give good advice when we don't know all the details, however the truth (and I mean actually the truth) is usually a good bet.
However, this is not always the case. Sometimes you need to conceal some things to show kindness. You need to evaluate how your news will effect your mom and your relationship with her.
Is she intelligent and open minded enough to recognize there are good reasons why you have "slowed down" and are moving on with your life? Or is she likely to shun you?
I think it is really important that you preserve your relationship with her - whatever it takes.
IMHO, your ultimate objective should be to try and free her mind, so you can both exist outside of the controlling influeance of the WT. Then everything else will fall in to place and you will live happily ever after.
Think of her first - above yourself. Be kind. Be respectful. Show genuine interest and offer heartfelt, sincere, and logical reasons for why you are proceeding as you are. Encourage her to consider carefully, why you and others like you are deciding to stop attending meetings.
Whatever you decide - I hope it works out well for you!
The Oracle