Mary is soft and romantic, but with a small head in relation to her body, she needs more volume and fullness. With very fine, flat hair, it is nearly impossible to create a soft, feminine look with a short hairstyle. A classic bob would draw her down and would need to be teased to have the right balance, but then would be too fixed and wouldn't last very long.
If we went short, she would need to tease everything to cover her splits and cowlicks, and that, too, would fall flat quickly. Not to mention, it would take a lot of time with too mature results. And again, it would not fit her romantic and feminine personal style. She liked her silver hair and was tired of coloring it. So how do you do a makeover? Since she likes her hair up and always wears her hair up, why not have THAT be her look?