If she's only twenty, then no, she isn't old enough for what I'm talking about. But I have to confess I'm not immune. I'm like you, I believe it is only polite to use the term that people want to be called. But I can't deny that while in a discussion like this I'll say people of color, in my own day-to-day life I say black. Not because I'm trying to be disrespectful or belittle other people, but because that's what I grew up with and that's what I'm used to. It's habit. (Not to mention shorter and easier to say. Yes, I'm lazy.)