As I remember from when Prongs got married, that's the normal way of things. It's really her day in a lot of ways, in any case. Usually us poor blokes would be just as happy with a quick 'I do', a bit of cake, and maybe a toast. Although, I always did think I wouldn't mind the dancing so much at the reception.
Sometime after the Full sounds perfect. The school can do without me for one dinner, I'm sure.