Shouldn't that be 'She had left home before she was 16.'?" People are often confused because English has so many past tenses and they don't know which to choose. In fact we choose past tenses in ...

And I would always say, with much emphasis: "Multiply that by 3." Believe it or not, there are 16 tenses in the English language. Some would even argue there were more. But I would stick to 16.