How Do I Tell My Mom I Have A Boyfriend?

Well were both 12 and he has been over to my house once. He asked me if my parents knew that we were dating and I told him that I was to scared to tell them. I mean im not hiding it, its on facebook and my mom stalk es my profile so soon or later shes gonna find out. He has told like his whole family and only my little sister knows. She sort of disapproves me because I confuse easily and get hurt quite often. Ive died a strip of my hair blue and isolate myself most of the time. Im super scared to tell my mom or my dad that Im dating him and i cant even think about it without almost puking so how can I do it?