ばか！バカ！　馬鹿ー月！

The problem was Miyokichi. Even though she knew perfectly well. That her own appearance couldn't be seen as less than twelve.

I can see where the translator has added sentence breaks where the author (I assume) added artificial pauses in what would normally be a single sentence. The question is, are there two solid sentence breaks in the original Japanese, or just the Japanese equivalent of ellipses (as would be correct in English)? And if they are three separate sentences, since they do make up their own paragraph, should we break them up further into three separate lines?

Sorry, just my inner grammar teacher bugging me... ^_^

I thought the same thing when I read it. If you say the line out loud, it's a bit like adding an after thought to what you were saying to make things clearer, but it could easily be one sentence.