Honestly, I am a little uncomfortable that she is getting built up to be the face of this movement which is so critical for our global environment and the survival of millions on our planet, when she may not end up being quite ready for the limelight. The real heroes in this story are the scientists, especially those trekking into remote places like the middle of Greenland to drill for ice core samples and such.
But she is just a kid, not a climate scientist, and she's had more of an impact than you or I ever will.
As for being unprepared... again, kid. If you want to dig in and engage with the science behind this issue, you can.