The button looks great but you might want to wait until AFTER you quilt it. Buttons and other large embellishments can be a nightmare if they're put on before quilting.
Also I like to say this: Don't insist that it be perfect. If you look closely at published quilts by professional quilt makers their points don't always match up either. A tiny mistake in a block looks HUGE, put that block in a quilt and it will make the tiny mistake next to invisible. Put the quilt on a bed, couch or on the wall and MAGIC happens!!! The tiny little mistake dissappears!