I'd start her with a cheap Mora knife.
First, it's easier to sharpen a slightly larger blade. Second, it's safer - no folding blade to slip and cut while closing, no chance of collapsing while used - just out of the sheath or not.
While big enough not to easily be lost (especially the orange handled one!), the handle is relatively small and fits a young person's hand well.
That's my 2 cents.
