I have epilepsy, was diagnosed at 11. It can run in families apparently, my parents were asked if there was any family history - there isn't but it can be a family thing.
I have had loads of EEGs over the years, plus I had a scan as well when I was diagnosed. It's all a bit scary but it's to make sure they get the right diagnosis so they can sort out the proper treatment for her.
Try not to worry if you can. Now I am a parent I can understand why my parents were so worried at the time, I had a few fits before diagnosis and looking back they must have been terrifying for my parents but I wasn't particularly worried I don't think.
My fits are stress-induced, that can often be what brings them on, sometimes other triggers as well. The EEG will help identify what triggers your daughter has if any - she will probably have had to breathe heavily as if out of breath for a bit, have lights flashed, etc, to monitor her brain's reaction.
I had the scan as well as I said, but in my case nothing showed at all - only on the EEG. I am on medication, have been since I was about 13 or 14, not til I'd had quite a few fits, and I function as a normal person.
I'm sure she will be fine and if it is epilepsy, will cope brilliantly.