A student who is well-read can pick up vocabulary and phraseology from places other than home, though I suspect she wouldn't be reading the type of material that would lead her thinking this way without encouragement at home.
There are some slight errors in usage of words that I find very consistent with the writings of a child that age, who is wise beyond her years in some ways but still not a fully mature writer.
However, the main thing is that whatever her age and whatever her background, the young lady makes some outstanding points. I only wish that many more adults shared her views!
Like other posters have said, young people like her give me hope for the future when everything else seems to be going to hell in a handbasket.