haha my mom is the same way. I've also given her tasks and it seems to help, she just really wants to be involved. My fiance reminded me that our wedding is a very important day to her too. All our family in one place and she gets to show off her little girl. Every time she turns into crazy mama I remind myself of this and I smile and my frustration goes away, well kinda goes away.
I agree with all the ladies, as long as your aunt and her aren't fighting all is well. Your aunt is probably happy to have the help.