Stepmom is forcing me to go to church?

im atheist and i do not believe in god or that jesus is god. i just dont believe that. i told my parents and my dad is fine with it but my stepmom thinks im just saying that to get out of church. what do i have to do to get it through her thick head that i dont want to waste my time listening to stories. i feel like crap this mornin and my throat really hurts but she insists that i go to church. what should i do? no i will not go.