Hi JohnBaggen
If you're able to return to this person, this is what you could do:
Take along with you a printed model release form (I think it would be better).
Ensure there is at least one person who is literate and willing to sign as a witness present with yourself and the model.
Explain to the model about the photo and what it will be used for in details.
Have the model make a mark where she should sign (an "X", tick, or any other mark)
Have the witness sign beside or below the mark (You will need to write the word "witness" beside that signature, and the signee dates the signature)
Make a note at the bottom of the form that the model is illiterate.
Make sure the rest of the form is properly filled out. Make sure your signature date, the witness signature date, and the model mark date all correspond.
I hope this helps
JG