A.S.
If I had to guess I would say that she is highly intelligent and curious about EVERYTHING. I was that way too, as a kid, and read everything I could get my hands on. To this day, I'm rarely bored and there are always books, articles, publications, etc. that I want to read and don't get around to.
My younger son is that way (not a reader though). He probably *could* get an ADD diagnosis if we tried for it (not the hyper version - he's not hyper at all). But he's also extremely smart (even on tests, and he's got a visual processing disorder).
The good news is that most girls develop the "executive functioning" part of the brain much sooner than boys (some boys never do it seems).
I would watch it for another year or so before I started to worry (and I'm usually one who likes to be proactive). I think alot of this could be her age. And maybe it's not. But the problem is you won't be able to tell for awhile.
Good luck.