How do I convince My Parents To Let Me Stop Being Catholic?

I was forced against my will to go to a catholic school from preschool to seventh grade, where catholicism was shoved down our throats, and where the children literally hated me because I was half hispanic in a white school. I literally had to hold a gun to my head and tell them if they didn't switch me to a public school, I'd kill myself in front of them. That school made me suicidal, and every Sunday night I would hold a knife to my neck or tie a rope around it. It never worked. But the religion was ruined for me around kindergarten. I'm a Freshman now, (almost a Sopre!!) with lots of friends. But my parents still make me attend the church where the kids that made me want to kill myself go. Every damn Sunday, with no exceptions. How do I get it through their thick-skulls I hate being Catholic and want to be possibly Protestant?