I can't speak to the ADHD question - although you certainly could have her evaluated for this - but your description made me wonder if something else is going on. Is she frustrated or stressed? Does she perhaps not want to perform in dance this year?
I have been told by a very well-repected pediatrician that ADHD is often diagnosed when in reality, there is a different issue causing the behavior in question. In school, this may be an LD. In other situations, there may be issues of perfectionism, or boredom, or...you get the idea. Maybe ask your DD what's going on - she may surprise you with some insight that may help.
