I guess? I'm not sure that I would put a hard age rating on it and I am planning to revise the content warnings. I probably wouldn't personally play this game with kids or teens but kids younger than 16 get sent to treatment programs all the time and certainly engage with all of these topics in their lives.
It's not written to be played solo, but you can definitely do character/setting creation solo - I'd definitely be curious to hear about your experience of it if you try it solo!
