This is the first time I've read this book, and the impression I got was that she was just a very average girl. She didn't have any exceptional talents, she wasn't a beauty, and in short, there was nothing truly spectacular about her that would set her apart from other girls her age or give her any distinction. She seemed to follow whatever interested her, but only as long as it interested her. Since her mother was understandably preoccupied with the younger children, she wasn't made to apply herself like she could have. I don't really see this as a learning difficulty so much as being left to her own devices much of the time and doing what suited her at the time (within reason, though, I'm sure.)