My mother just relayed this story to me about my 5 year old niece. Her mother, my sister-in-law, was at dinner with her little girls and a family friend in a restaurant and her oldest was sitting there looking around and she heard her singing
“There are white people! There are black people! We’re all just people…”
So when they got home and my sister-in-law told my brother, he sat his girl down with their bulldog Max and explained, “Max is white here. Max is black here. Max is brown here. But he’s still just our doggy Max!” So my niece had her first real lesson on all the people in the world.