When I was a tween, the trope of a spunky self-sufficient girl was very appealing and I read Island of the Blue Dolphins, along with Julie of the Wolves, many many times. While it has (mostly) fallen out of fashion, my 4th grader is in a very large class with an older teacher who is running the students through a series of classic novels accompanied by basic comprehension questions for homework. My son's group is currently working through Island of the Blue Dolphins.
Karana was barely 13 when the story began. It struck me that at 13, she already knew enough of the adult's work to be self-sufficient in a way that few 13 year olds would be in 2013. I can still see what appealed to me as a younger reader, but as an adult, some of the descriptive passages were a bit tedious.