I have a daughter and son who have both seizures and migraine. My son can have a normal eeg at times, other times there are some abnormalitiey.
Topamax can be a good med for both seizures and migraine....
She will go far if she can learn to work around her triggers. You mentioned her cycle (a big one for my daughter too), stress....Lack of sleep can be another. Flickering lights affect my daughter a lot also....
You might ask if she can up her meds just before her cycle, by a pill or two, I have a friend who does this.....Ask the neuro.
My kids are 15 and 13, so I can understand that at 17 and with college ahead it is very scary for you. Educate yourself all you can on seizures and migraine.
Emedicine is a great source for both migraine variant and seizure info...
Epilepsy.Com is also very good and accurate.....
Hang in there mom!