It's just a recital, for goodness sake. Tell her it's for fun and that you will cheer her on. She is having her own little crisis due to her first, possibly first, time on stage with this type of activity and she is having her own bit of stage fright. How about trying to make it more fun and less "Oh My Goodness".
All teachers add stuff and tweak the routine until the last minute. I agree they should be doing fairly well at knowing it but the may just have a lousy teacher. You may have also caught them on a bad night, after all, Spring Fever is rampant at this time, plus school getting out, stress from practicing to perform...I can only imagine the stress she is feeling.
At this point our dance teacher is tweaking things like head positions, she even changed the front line and the back line around last week. There was one woman who decided she just could not afford 2 dance costumes so she dropped her daughter out of one, her girl is my girls dance partner in one song, they do things together. So, the teacher had to change the dance around again.
It is chaos until they enter the stage then it all comes together. If it doesn't then so what, it's not a competition or something that is required for life.
BUT it can be a good or bad experience that can influence her ability to be in front of people for the rest of her life if you don't turn it around and tell her it looks wonderful and that she is doing a great job, that it's is looking much better.
It's up to you momma to turn it around to a positive. If it stinks at recital you can chew the owner out and demand a refund or something. But her spirit needs you to lift it up and build it up right now.