There were 3 black kids in my neighborhood growing up, all from the same family. Their parents were white. I didn't know what "adopted" meant, so I thought that under certain conditions, white parents could have black kids.
My high school was about 2000 students, and only one of them was black.
I didn't see my first truly black person, skin so dark that it glowed blue under florescent lights, until my folks took us to tour the Smithsonian in DC. I was 10ish? I saw her on the Metro and couldn't stop staring (sorry). Opened my eyes to just how wonderfully diverse people could be.