T H I S M E L L I N G E R

Hallie is in preschool now, two days a week. Guy and I get to drop her off in the mornings in front of the school. This morning when the lady came and got her out of the car, as usual, she jumps right out and grabs her backpack and lunch box. Guy started to fuss a little bit which is pretty normal. She is standing on the sidewalk outside of the car and says, "Sorry, Bub, I can't stay. Love you Mom!" and closes the door and walks into school.
How old is she again?