I think the slow fade is the best thing if you want to keep contact with family members. Since you already told your mother you do not believe anymore she may feel obligated to talk to the elders.
As somebody already mentioned only you can make this decision. Can you handle shunning by your Mother or other family members?
Do you think they will shun you? Personally I know my mother and father would never shun me. My siblings probably would so I choose to remain faded.
Good Luck with whatever you decide.
Sandy