CMS/Colloquium knitting - a false start

This is what I worked on in CMS and Colloquium last Thursday.  It's an afghan for my cousin's son.  He's getting a new sibling in a few months, and my mom and I are making blankets for him and for the baby-to-be based on the same pattern (Vexillo by Berroco).  The blankets are constructed by sewing together a series of 6"-wide garter stitch strips.  I wanted to make sure my work turned out the correct width, but I didn't have my measuring tape with me, so I used my pro geometry skills to create a 6" square of printer paper to check.  Unfortunately, as you can see in the photo, the strip is about an inch too wide.  My gauge is way off, so I'm going to start over again with smaller needles.  Luckily, it goes fast!  What you see in the picture is less than an hour and a half of work - it took me half an hour and about two inches of knitting before I figured out how to slip the edge stitches the right way to get a nice selvedge edge for seaming.