Should I tell my Christian grandparents that I'm a atheist

I tell my grandparents that I am Christian but Im getting tired of lying to them, it makes my cry at night, i am writeing this in their house. I am scared of what my grandma might do. I need an outside opinion. Should i tell them? edit: they make me go to church sometimes and I'm uncomfortable there

another edit: my parents are great and supportive it's just my grandparents