"Don't laugh at me."

Whenever Alice says something unwittingly clever or cute, (which is quite frequently these days), Zac and I will often laugh.  The other day, when we were laughing at something she said, Alice looked right at us and said, "Don't laugh at me.  It makes me mad."  At first I assumed this was something she picked up from a kid at school or something, but she keeps repeating it and seems to be earnest.  Zac and I can't bear to not laugh at all the funny things she says, so we keep trying to explain that we're laughing because we like what she said.  Nevertheless, it is a somewhat sad turning point, because she is definitely becoming more self-conscious and self-aware.  She's also starting to back-talk.  I'm not ready for this yet!