When I've complained about curriculum it's because, from what I saw in the text books, the little Oni was ready for 7th grade math this year.
That's a wonderful point, Oniya, for several reasons. As you say, based on the curriculum presented in the book, the little Oni was far in advance of the curriculum as published in the textbook.
For years two states, Texas and California, drove the textbook industry. They were the largest purchasers of textbooks and publishers catered to each states' standard, largely building the book around them. When a district in say, Kentucky, bought a book they'd get a modified (or not) Texas or California edition. This often mean that the curriculum teachers and parents saw were based on Texas or California standards and not at all related to your state's standards or, indeed, may not have been age appropriate. Both Texas and California service an extremely large percentage of students who are in poverty and ESL.
This is beginning to change as most states have adopted the Common Core curriculum. Publishers have basically abandoned Texas and are now working to create texts that work for the majority of the other states.
So what I believe may have happened is you and Little Oni got a textbook that was far too low in level for her for these reasons and because she's scandalously smart like you. :)