Welcome!
Generally, I am an advocate for testing only if 1) there is a functional question to be answered or problem to be solved, or 2) if it will provide access to resources. In your DC's case, it sounds like the teacher is describing functional problems to be solved, with unanswered or unclearly answered questions. So yes to #1.
If further testing is advisable, given that the recommendation is coming from her classroom teacher, it would make the most sense to have the school conduct testing. It won't cost you anything out of pocket, and it will be maximally likely to be accepted by the district. Having good grades may or may not be a rule out for an IEP, depending on your state regs.
ADHD takes many forms, especially in girls. The previous assessment (done when she was very young) ruling out ADHD may or may not be accurate, especially as what appears developmental at a very young age can become clinically significant if it persists into older ages.
