Quilt in a Day Forums

I have been collecting bandannas to make a quilt for my king sized bed. I am very new to quilting, the only other quilt I've made was a tshirt quilt. I was hoping someone could help me decide whether or not to back the bandannas with interfacing? My first first instinct was to use interfacing, as I did on my tshirt quilt, which turned out beautifully. I read on another website, though, that I should not use interfacing on a quilt, that it's better to deal with the ends raveling after it is sewn. However, I realize that a bandanna will ravel much more than regular quilting cotton. The bandannas I'm using won't work at the size they are---many of them say "Made of 100% Cotton", and I feel 21" squares would look odd--so I do need to cut them down.
Thank you in advance for any guidance!
-Vivian