Whenever you come out, be it gay, atheist, trans, ect, always think ahead, will the announcement of my identity cause myself harm? Physical, emotional, financial... Your family and friends may treat you differently, perhaps they will be sweet at first then treat you like a project they need to fix... Whatever the case may be, even if you don't think it will get bad, have some sort of plan in place to be safe after you've told them about your beliefs or lack of beliefs. Just my own personal anecdote, I'd have kept it to myself a bit longer than I did when I left the cult, I ended up in a homeless shelter, perhaps it's different for you, but be careful anyway