Second, it depends on your overall matching dress, some dresses are suitable for matching shawls, and some dresses are not suitable for matching shawls.
Thirdly, if your wedding place is outdoors and the weather is cold, it is ok to wear a shawl. If it is indoors, you can choose not to wear it.
It's best to have a look at the pictures, or ask the image designer at the clothes shop. They will be more professional.