The pushing of the button and seeing the work she chose to try must have been a thrill for her. My grands always are tickled when Mimi sets up the machine and lets them push the pedal. I try to teach them a little hand sewing first. I've had my garden hats decorated by different patches from old scraps, I've had pillows made of my scraps. They get bit by the bug when being allowed to touch and learn. You've begun a great thing for her. Give her a big hug from a Mimi in NC.
You know, I'd give her the scrap bin, a lap size piece of backing and let her make her own design. Don't make her learn to many rules at once or she may decide it's all to much like school. Just give her the thoughts of 1/4 inch (she's likely not learned fractions yet, the END of 2nd and 3rd grades are the fraction learning) with painters tape on the machine to meet it and let her use all size blocks. See what her color sense may become.
You are so fortunate to be able to teach her. Mine will be grown before they come back from Alaska, but the two still at home have promised to learn to sew with me. I reminded them I don't forget their promises. lol lol
Sharon