This should be an image of the regular way of wearing not a shawl but a scarf (which is smaller than a shawl but in other respects essentially the same thing according to this source). Wearing it backwards should mean that the ends hang down the back.
You were reading a story.
If we are to answer this question for you with any chance of being accurate, you must tell us more.
Where in the world is the story set?
What kind of shawl is this?