You don't need a bunch of fancy rulers. I started quilting when we still tore the fabric, not cutting it. I still tear on some quilts, and swear that I won't do it again, but still do. I use an Altos QuiltCut2 which has a 24" ruler, but also use a 6"x24" lipped ruler, and the 12" and 6" squares. I have way too many rulers that I have purchased and never used.
Be accurate with your cuts. Like someone said, and eighth of an inch multiplied by eight is one inch. And make sure that you are sewing a true 1/4" seam. Good luck. And don't be hard on yourself. It will be a lovely quilt, and I hope you pose pictures.
Welcome aboard!