I don't really remember not knowing. In conservative Christian circles, Corrie Ten Boom is pretty highly thought of and I remember learning about her at a young age (6, 7?). I read Diary of Anne Frank on my own when I was 10 or so.
I actually don't think I was ever taught about it, other than in passing (1 part of a single history lesson on WWII). Most of my US and World history classes never even made it to WWII until the last few weeks of school and then we had to cram in as much as possible. My WWII and post-WWII to present knowledge is abysmal.