Funny comment

Matt and Nettie were having a discussion this morning. Below you will find the exchange:
Nettie: "What was your hair like when you were a little boy?"
Matt: (Wasn't able to hear this reponse due to other noise.)
The conversation continued with Nettie asking about my hair.
Matt: "Mommy's hair used to be a lot lighter when she was little. Sometimes it gets darker as you get older."
Nettie: "My hair is getting darker! Daddy! That must mean I'm a grown up!"
She continues to sing, "I'm a grown up, I'm a grown up." over and over and over.