As you said, first, find out if she really wants to do this.
You might also want to check out her "klutz" factor.
Then make something real that doesn't have to "fit" - a tote bag, a pillow, a scarf -
My granddaughter made herself some fleece blankets - using two layers of fleece - the first one she did the tied fringes - the next ones she sewed together -
My granddaughters were using my rotary cutter when they were like 6 and 8 for making Barbie clothes and accessories. They never cut themselves - more than I can say for their grandmother.