Here's a link to Mari's first published modelling work, for Carter's clothes (founded in Needham, MA where Mari's grandparents live).
In case it expires as the catalog changes, here's the image:
Update: to answer a couple of questions I've since received, yes, she has an agent, Dynasty Models in Boston. They are the ones who found this job.
She was paid an hourly rate and gets no royalties.
And no, she didn't get to keep the clothes (they have a bunch of kids wear the same outfit trying to get a couple of usable shots). Her look in this shot is called Violet Steel, an homage to Blue Steel.