"Doing my periods"

Today while driving to church Kate was reading one of her little books from school. She would read a sentence and then take a huge breath/sigh. After a few times I asked her what she was doing because I had no clue. The book wasn't about smelling things or anything. She told me that she was "doing her periods." It just cracked me up. Obviously, her teacher makes a big deal about punctuation when reading. I just LOVED it..."doing my periods." Someday she will have a whole other thought for that comment...hahahaha!