S.E.
I think you are correct that you should be able to go have your daughter tested but ir may cost you to do this. The reason it may cost is because the state did not receive any money for your daughter because she was not enrolled. The district uses the money they get from the state to fund testing programs at each school.
Check with ICHE http://www.iche.org/ to see what they can do for you. If you are involved with a home school workshop program like Heartland Home School Workshops in Crystal Lake ask the other parents what they have done. I know there are families. from Huntley that attend Heartland Home School Workshops, I have a boy in one of my classes at Heartland that lives just outside Huntley.
Good Luck,
S.