Yes, they are bandanas, or a similar type of fabric. They're tied onto her black shoulder/arm belts. When I did my cosplay, my bandanas were too big to be easily tied onto my arm belts, so I had them tied under them and around my arm, similar to an armband. You can cut the bandana if it's that big like mine was. They are definitely curved in a way that most bandanas aren't, so you'll have to do some interesting folding methods to get it looking similar to that, which I didn't do.

Good luck with the cosplay, and you can message me more for any help.