Please help me, r/atheism.

I am 14 years old, and an atheist (not agnostic). I am currently part of a Catholic family, and seeing as I am in 8th, will be getting confirmed late winter/early spring. I will most likely go through with the confirmation to be done with the church education program and to get a new suit. But I feel tired of being an "in the closet" atheist. I feel my mom may suspect something, but she just throws it off as me being annoying or trying to be funny. What I am asking is if I am at a good age to come out, and if it is, how can I do it with the least conflict.