I was a boarding school product from the age of eight, and I hated it. Though I do have a theory that boarding school is good training for writers because it's so desperately lacking in privacy: you make space for yourself by having an interior life.
Guernsey itself was overcrowded, but its cliffs were utterly empty. I spent a wonderful year with a friend, climbing them. It was sheer magic: you went from this pretty, busy village of an island to the sea cliffs and heard nothing but the gulls and the waves.
When writing fiction, you only have to know enough to be convincing on the page. I mean really convincing, of course - but you don't need academic depth.