Circular Knitting Needles Necessary?

Thank you all for the response. It makes sense now that you mention the bulk of the project.

I have another question…

The yarn called for in the project is not the yarn I want to make it out of. I would like to use a fine cotton in brown, which I have already purchased. Is it okay to interchange these yarns? They seem similar in size and weight and I just prefer cotton in any of my clothing.

Thanks again!