Luna Moth Shawl

I started this project a couple of days ago, and it went well until the last few rows of the second body chart (so I know the pattern's right). I ended up with an extra stitch on the left side. I counted and counted and compared and couldn't figure it out. Did I put it down to be frogged on the morrow? No, that would have been sensible. I knit four more rows. I don't know why. Well, I started the frogging yesterday, and I still haven't found the problem. I will today, and I'm liking the pattern. The yarn isn't as grass green as I was hoping, but neither is it as grey green as it is showing in this picture.