"Let's just pretend I'm two..."

Yesterday, Heidi was getting pretty grouchy, so I told her she had to have 3 minutes of calm-down time now (since she's now three). It used to be more like 2 minutes of time-out when she was 2. When I told her she had to sit quietly for 3 minutes of calm-down time since she's three now, she said to me "Let's just pretend I'm two... Pleeeeeaaase?"