Originally Posted by childcaremom:
Thanks! You are all right, of course.
I don't know why I feel awkward enforcing late fees. I have no problems with enforcing any of my other policies but anything involving money, I am like a limp noodle. 
And she was only 30 minutes late with payment. (limp noodle)
There's still time to fix this. The day before payment is due next time offer a reminder that she was given a freebie for late payment last time but it needs to be on time from now on.