Ok, you’re trying to stay true to yourself by telling your dad that you’re out. What do you honestly think will happen? Do you think that your dad is going to get upset? Sad? Angry? Disgusted? What purpose does such an encounter provide?
You know perfectly well that he’s likely going to get angry and shout disgusting things at you – do you think this is the time your mom is going to pay attention? She hasn’t for your whole life so why would anything change now?
Honestly it sounds like you’re causing drama to be dramatic. If that’s what you want, have at it. But I really don’t think anyone is going to give you want you really want or come to your defense after you pull such a stunt.