Why don't you change?

The next morning after I follow my older daughter to school, when I was waking her up,
Older daughter: Mommy, why you haven't change yet?
Me: Why should I change?
Older daughter: You have to follow me to school.
Me: I can not follow you to shool today, tomorrow OK? I have already follow you to school yesterday, so today I have to stay at home with your sister.

Luckily she said OK and could accept my reason.