I'm going to ask my stepmom not to force her politics and atheism onto my sister
She is just a kid.
I need her to realize that she needs to be strong.
It can be difficult with a sibling when you want to help them but their parent wants something else for them. But it is okay to help them out anyways, they might thank you later on when they realize that you wanted the best for them.
I might have to confront my stepmom about it.
You should if you feel it's that big of an issue. Maybe suggest that she should bring up these things when you're sister is old enough to understand.