Something is not right about this Fox story.
That girl was born in 1585. She was 12 by 1597. If so, then this is a “16th century dress.”
Countess of Roxburge, Jean Kerr (Ker):
https://en.wikipedia.org/wiki/Jean_Ker,_Countess_of_Roxburghe
The ship sank in 1643, when the countess was almost 60. Maybe she just had a small build, or was corseted extremely tightly, or the display or photograph gives a mistaken impression of the dress size.
It was that leap century they added in 1200.