Have you asked her what she'd like to learn? Is she attracted to the modern quilts or the traditional patterns or applique? Does she like bright colors or muted ones? If you start her on a project that she's excited about, it will so much easier for her to learn. As for size, I'd start with a 16-block with borders which will produce a size that she can hang on the wall or use as a bed topper or a baby quilt.