Flower Girl Dresses

My fmil is making the flower girl dresses for our two flower girls. I really didn't like this idea, but she insisted and my fiance told me to let her. I told him after she offered that they needed to be done 1 month before the wedding. He said okay. We went with her to JoAnn's to get everything we needed or so I thought. We bought a pattern and material, but she read the pattern wrong. She has been sewing for over 50 years and has made lots of clothes so how she read the pattern wrong I have no idea. She forgot the lace at the top of the dresses, the inner lining, buttons, and about 10 yards of tulle. I had questioned if we got enough material, but my fiance said she knew what she was doing. Fast forward about 4 months, her and I went visit my fiance's brother, his wife, and their four children (two of which are the flower girls). My fmil was supposed to make the dresses and the flower girls were going to try them on, but my fmil didn't realize the girls were on spring break so she barely got any work done on the dresses and she made a mistake which required her to undo a good part of her sewing. It has been about a month since then and she has not worked on them since. Only about 75% of the top of 1 dress is done. She told my fiance both dresses are almost done, which isn't true. She has about 1 month left to do them since I said they had to be done 1 month before our wedding. I don't want to fight with her or my fiance about this, but I feel that if the dresses aren't done 1 month before like I requested that I have no other choice, but to buy other dresses for the girls to wear and have them mailed to their house so they can try them on to make sure they fit. Otherwise, my fmil will finish them right before the wedding and the girls won't get to try them on. Do you think it is unreasonable for me to request that they be done 1 month before the wedding so that they can be sent to the girls to try on before the wedding? If they aren't done, do you agree that I should purchase other dresses and have them mailed to the girls' house? What would you do?