If it was a casual dress then it wouldn't be too much as long as you wear sufficient underwear in case of wind on rides and such. The heels I expect would be uncomfortable, if you want that boost, I might go with wedges instead. But flats would be cute with a casual dress too.
You CAN wear it, it's just the opposite if a good idea. This about your feet after walking around and standing in line for hours. Also think about sitting on unclean surfaces in a dress or trying to buckle into rides- difficult
You *can*. Your feet will probably kill you by the end of the day. Skater dress + sneakers at the very most. You're there to go on rides and get burnt to a crisp and eat terrible/amazing junk food, not look like a beautiful and high maintenance biddy.