The low-hanging fruit given this current iteration of the logline is that you can easily pull out “and journey through an impoverished land to find a saviour, which she later learns is actually herself,”. That part is the plot, but doesn’t need to be in the logline.

So you have the protagonist, the high school girl, the goal… to save the world… the conflict… confronting the powerful government. The stakes… end of the world. The urgency… have to do the goal before the world ends….

The inciting incident I think you should change. Learning about the end of the world is a lost opportunity to tie in HOW a high school student ended up in this mess. Maybe have the inciting incident be like when the kids walked into the closet in Narnia. The “how they ended up in never-never land”.

You can trim it down, like for example with my first suggestion, but… all the pieces in the formula are there, which is great. But I think ironing out the hook will be more challenging.

Why do people care about your story? I see this notion of a privileged girl journeying into an impoverished land, which is interesting, but it doesn’t look like she has to overcome that privilege in order to save the world. It’s like when I toured Ward 9 on a bus tour a year after Hurricane Katrina happened. However, Ebenezer Scrooge must learn generosity to save Tiny Tim, for instance. That is a meaningful character arc that is interesting to the reader.

I’m thinking something like this:

When a privileged high school girl is lured by a magical spirit into another world, she must lead the rebellion of its impoverished, enslaved people and overthrow a powerful monarchy before she is allowed to return home.

Okay…it doesn’t have to go all Braveheart…. can keep it non-Bravehearty…

When a privileged high school girl is lured by a magical spirit into another world, she must save an impoverished, enslaved people from a powerful monarchy before she is allowed to return home.

Either way, you don’t need any details of a mountain, or how she tries to save them.