Behavior of 12 - Year Old Girls In the 18th Century

I am having some trouble figuring this out. In the novel I am writing, the book starts out when the main character is 12. Now, I just turned 13, so you might think, Oh Why is she asking this? Well because It was probably different then. Can anyone find out for me how they would have acted?

Like, more like 9 year olds today? Still little and naive or with a sense of maturity? thanks.

I'm not entirely sure about the 18th century, but it can't have been too different from the 19th century, and they were actually quite mature then. More naive about some things like sex and, if they were well off, the state of the lower classes, but using quite a sophisticated vocabulary and having a better grasp of grammer and meaning than some older people today. They may not have talked like it, but they certainly wrote in quite a formal style. Basically, they were groomed to be adults in minature.

Thanks!