To people who have left the religion they grew up with, what was it like telling your family?

I was raised Christian, Baptist actually, but am now agnostic. I have not told my family yet, I'm trying to break it to them slowly. I have given my mother a Richard Dawkins book and asked her to read it so she can better share her faith with an atheist. It is my hope that reading such things were make her more open minded and ready to hear me out when I tell her my decision.