Aaah, your first quilt! There was (of course) a time when I was at the point that you are now. Having learned the hard way, I would advise that you buy fabric that is not so expensive that you would "beat yourself up" if the end result is not to your liking, BUT, on the other hand, DO buy fabric that you like so that you will enjoy your first quilt project when it is finished. Buy 100% cotton, not too loosely woven and not see-through. My first quilt is a king sized bed quilt and, more than 10 years later, I am still hand quilting it. Some of the fabrics in it are polyester and some are just weird and some of the colors are poorly placed, but the quilt is well worth finishing and DH says it belongs to him ... he loves it.