If you would read my reply again, you'll note that I said, "I downvoted you because of the suggestion that "most books" are appropriate for (and interesting to) 8-14 year old girls."
Frankly, I don't think that's controversial enough to have to explain.
First, it's flat out wrong to group 8-14 year old girls together. The sheer amount that girls grow between those years makes that highly questionable. The kind of book that the average 8 year old would gain from would be insulting to the average 14 year old. And the kind of book that a 14 year old girl would gain from wouldn't make much sense to the average 8 year old.
And yes, there are outliers, but if your child is an outlier, for the love of all that is holy, spend time in bookstores with her and figure out what she's actually interested in. In distributions like this, outliers tend to have very strong interests that overwhelm all the social pressure. If you're dealing with an outlier, figure out those interests and cater to them.
Second, let's look at the word "most". Do we have to talk about how most popular fiction geared towards adults may not be appropriate for the average 8 year old? And what about interest? I'm a 40 year old man who reads voraciously yet "most" books are neither appropriate, nor interesting to me. There isn't anything wrong with that. It's just that we all have interests.
It's annoying when someone edits a comment to ask why they were downvoted. But, it's flat out dull when they edit a comment and then make an entirely different reply to ask the same thing. That adds absolutely nothing to the conversation.