I agree with Miriam....I had a wee bout of this myself with my cousins, but as time went on, I realized that I shouldn't have expected so much out of people that have never really supported me (which was VERY hard for me because I ALWAYS support them and felt like this was totally unfair). But I didn't want to look back with regret...this should be your time, planning should be fun (with a few hiccups along the way), and I would just not bother showing her anymore of your details for her approval, and would agree, treating her like any other guest from here on out is in your best interest. Everything will be wonderful, and in the mean time, we are here for a two pager rant if you need....
Keep Smiling!