No, don't call the cops on your parents. After everything they do for you, you want to have them arrested? Have you considered how your life will turn out? Where will you live if your parents go to jail? What if you have to change schools and your social status changes to girl they like to pick on?
Besides, unless they have pounds of the stuff, the cops don't really care. In some states, it'd only be a ticket. They'd have to go to the trouble of getting a warrant signed from a judge, and they'd look pretty stupid coming back to that same judge with people they arrested for having a couple joints.
Just don't do it, kid. It's not worth it. Have a conversation with them about it. The least they can do is hide it from you.