Erm, sounds like you problem is related to your GF not letting you know she has a fear of heights in the first instance, specially as you know the height of the stadium..
I’ve a fear of heights, I’ve cried like a baby on the 1st platform of the Eiffel Tower, been shaken at the top of the 17th floor at a friends Canary Wharf Appt, almost been sick to the point of blackout at trying hangliding (I know, I know, but I had to give it a go Non?)
but I’m open to let anyone know about it now. I’ve tried several methods to cure it but now, now I can’t be bothered and my lifes fine and dandy as it is thanks.
Get her to look at the horizon line all the way through..