To give you an idea of what you can do with certain sizes, I have collected them here for you. I hereby state the material, size and name of the design. I think this can be useful for your decision. The Day Dreaming At Lucky Cat Tree is 127x127 cm, which is huge. As you can see, even though it's Silk Habotai (100% Silk), it's definitely possible to wear as a top or around the head.
My friend is 1.69cm tall. Usually she is a small but with items from Zara she wears medium.
If you have any questions, please do not hesitate to contact me. I would love to help you with your new scarf <3!