You are being way too hard on yourself. That is not an ugly quilt and you should be proud of such a great start on your quilting career. The blue sashing looks best to me but then I like lots of colour. Many first time quilters wouldn't even attempt sashing. My first quilt was just 8 1/2" scrappy blocks stitched together and I thought it was beautiful. Finish it up, enjoy and start quilt #2!