I am sorry that you are going through this. My younger sister who is 28 was diagnosed about a year maybe almost two ADD. She probably would have when we were younger too but I don't think it was that common knowledge. She has trouble with tests too. She is taking meds since she started taking college classes. She says that they do help and can tell when she didn't take her med that day.
I hope that you see an improvement with your daughter with the medication.
Kyia