Probably many of us here. I realized I was atheist recently and I'm 50 but my daughter realized it in college. I say realized because for years our whole family went through the motions out of tradition but I don't think anyone was every really buying it. My daughter was the first one to be able to break the spell of the Catholic guilt trip and the rest of us eventually followed suit.
Good for her! Now that I think about it myself..I believe I was following the family tradition myself as I was apathetic about religion in general and felt that people should just believe what they want..I didn't really take a stand until fairly recently (hence, my atheism).