Pupils at Hogwarts include sons and daughters of magicians, but this is not a pre-requisite and indeed the best student, Hermione Granger, comes from a Muggle family. Harry Potter's father was a powerful wizard, but both his parents died fighting the chief villain of the saga, Lord Voldemort, and Harry grows up as an orphan in the home of uncle Vernon Dursley, whose whole family hates magic and despises Harry. Courses include Charms, Potions, Defence Against the Dark Arts, and so on. There is more to make the books entertaining. The basic plot is, as expected, good versus evil.
Potter is a hit with readers of all ages.
Readership includes adults, but Potter is also credited with making reading books more popular than it used to be with junior teens and even younger kids. Then, almost no reader would have considered the existence of beings such as Pinocchio's fairy godmother as a serious possibility. Magic is the main usual metaphor for life in fairy tales of all ages. But he is not even in the same league with experienced wizards such as the dark Lord Voldemort and his main minions. Yet, he defeats them.