This is such terrible advice its insane.
You have no idea what the other side of this situation is. Op could be a drug addict, suicidal, straight F student.
The step mom could absolutely be in the right here.
And when you involve child protective services in your life you better be ready to go live with fucking strangers and separate from your siblings.
NEVER involve cps unless it's an emergency. This is not an emergency. This isn't even against the law and not even close.
Reddit is fucking dumb and wrong and none of these people giving this shit advice, have kids or have been in the system, or have any fucking idea what they are talking about.