@Leslie714 There is no "fee schedule". Each host sets their own rules, policies and fees for such things.
If you are going to charge for monthly cleaning, that needs to be stated in your listing info, and worked out with the guest before you accept their booking. You can't just spring extra fees on guests after they book.
As a new host, you shouldn't be taking long term bookings anyway, until you at least have some experience and know how things work. A guest who stays over a month isn't a guest, they are a tenant.
I would not accept another 3 months on this booking and you really should just eat thhe cost of the monthly cleaning, as this wasn't made clear to the guest when she booked.