You can't be forced to go to any meeting.
Your mom is using coercion, a threat that she is going to kick you out of the house.
But since your stepdad says no you should still have a roof over your head.
If an Elder wants to meet with you....... remember that your mother has probably told a few Elders about your 'apostate' beliefs. So she is one witness against you.
If even just one Elder wants to speak with you and you mention the same issues that Elder will be the second witness against you. The Elders would now have the Two Witness's they need.
You need to have one issue that you claim has seriously stumbled you. Child sexual abuse....... it is both a crime and a terrible sin. Your fierce reaction to child sexual abuse may be the result of having been 'fondled' by a family member, an uncle or a cousin.
I know that happened to me...I felt shamed and never spoke about it. I also never went into a private room with that person again when he wanted to play doctor.
If something did happen to you I'd have a talk with your stepdad ......not your mother.
If an Elder reach's out to you. Simply say that you are now praying to Jehovah and it seems to be helping. "So brother Elder, I appreciate your reaching out to me and if I can get past this pedophile issue, with Jehovah's help, it will help me clear my mind."
After that you go out job hunting LOL.......... Dude you need to get out of the house and do stuff that you can enjoy. Volunteering to help your community on some level would be a start.