I am mostly a self taught quilter. I came accross one of my first quilt blocks. It was a Cardinal on a branch with leaves made from HST. I was shocked, no two squares were the same size. On beyond bad, although I sure didn't see it when I made it. Maybe if I had taken a beginner class I would have been a better piecer sooner but again maybe I would have been discouraged and just quit. The important thing is don't let you SIL be discouraged, stress the fun, she will see her own mistakes in time.