In RPGs, it’s important to make sure that everyone has a good time. To that end, have a quick conversation about what content in the game everyone is okay with seeing and what content they’d like to avoid. Be honest with your friends - and if something comes up later in the game that you didn’t think of, you can always add to the subjects you’d like to avoid. Generally, there are four levels of content:
What we want to see: What are players excited to experience in the game? As a group, you should try to make those things happen.
What we’re okay with: What are players neutral about? That is to say, what doesn’t matter to them if it’s there or not? Most of the content will fall into this level, and anything the players don’t discuss will fall into this level.
What we want to gloss over: What don’t players want to experience in the game - but are okay with having as subtext? Sometimes, we’re okay with things being alluded to at the table - just not described. These are things that no one will be describing but that might serve as backstory. (For example, “I don’t want to have to describe or hear any descriptions of bullying. That can happen in the story - just let’s not describe it.”)
What we want to avoid: What don’t players want to happen in the world of the game? These are things that shouldn’t occur anywhere in the game - on or off camera.