While you may have room for her till Oct. Many caregivers and afterschool programs are filling for Sept and it would be better for the child to start the new program at the start of the school year so they develop those friendships and routines rather than changing. As a parent I would be very upset if you waited till Sept to tell me of the change once all the good spaces are filled but at the same time if you tell me now I am going to make the switch for the start of the school year if I can. Guess it depends on how much you want to upset the parent.