I want to go scream I'm gay and proud but I can't, what should I do?

I'm finally to that point where I've accepted that I'm a lesbian and I'm so proud that I want to go to the top of my roof and scream at the top of my lungs that I'm gay. I've already told a couple of friends who were fine with it. The only problem is my mom, dad, and stepdad. I honestly don't know how my mom and dad would react but I know how my stepdad would. My stepdad has this burning hatred for anything LGBTQ related. You can't even bring up Caitlyn Jenner or Ellen Degeneres without him yelling at you to shut up and never say those names. If I told him I was gay, I think he would get violent, plus he is a karate instructor who's already a jerk so I am scared of him. I know if I told my mom and dad, they might be upset at first but they would eventually accept me. What should I do? Keeping this from people is killing me.