First off, you picked the right block to "mess up" on. That block can be added to infinitely until you get the size you want.
Second. Get a copy of Elenor Burns "Quilt in a Day" for Log Cabin. You will learn so much bout how to avoid simple mistakes like seam allowances. You will learn how to look at a pattern and piece it the most efficient way. You will see the many, many ways to put Log Cabin Quilts together. My favorite is "Barn Raising".
Lastly, don't worry too much about how little you know about sewing. I never sewed a single stitch until I started my first quilt (a Queen sized Yellow Brick Road). And I have the added disadvantage of being male *L*.
My first Log Cabin Quilt:
tim in san jose
Sevens
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