How can I tell my parents I'm not Christian like they are? [Spirituality & Religion]

I am in no way a Christian. I curse sometimes, but it's easy for me not to, and I don't complain about not cursing. They do force me to go to church, which I consider a waste of time, and force me to read the bible and write summaries on what I read on (another waste of time). I've been to church for 16 years, and I've heard all of the sermons and songs. It means nothing to me. How do I tell them that I don't care? They can make me because it's not "unlawful," and since they legally have possession over all of my property, they often threaten to take away my bank account (in which I have earned a few thousand dollars). I'm not a legal adult, and by law, my money isn't really "mine."