collapse of the old society

Depends how you look at it. Knowing things have a high likelihood of getting bad helps her focus on skills that are not dependant on a thriving and stable society.

Besides that, she is a well adjusted teenager, who is happy with life, has good friends and recognizes unhealthy behaviour in others.

As with everything else I teach her, this is just a small part of the whole that allows her to keep thriving in this world, while maintaining good mental health. I think most people would consider themselves blessed to have a teenage girl this well adjusted.

Protecting children from the truth is the unhealthy approach. You don't doom and gloom it, you explain it it calm rational. There is a method to the healthy sharing of information that doesn't crush a person's psyche.