I've not taken a class and most of what I'm learning is from books and the wonderful people on the board. I would like to some day to learn certain techniques but am glad I haven't yet. I've learned the importance of the 1/4 inch seam, matching points and cutting accurately. I think if I had a teacher like your sisters I would have quit learning to quilt. I had a home ec teacher who almost kept me from learning to sew because of a similar attitude, I'm glad I didn't let her. Keep encouraging her and helping her, you may be able to help her enjoy quilting, something her teachers seem to be sucking out of the experience.