Personal awareness of how you best learn is significant, and likely has an even larger impact for the highly gifted; as it may very well be part of the mojo. If the format isn't working, then she should be able to regroup and look for the right context to learn the material.
But to prove that, maybe she should describe what an ideal AP biology class would look like and how that would help in one specific area she's found this course too hard.
However, if the inverted class doesn't include an active Q&A at the beginning of the classroom time, then I'd let her drop it.
