It is possible, if all her income had taxes taken out and she didn't make much, then she won't. However if her income was considered misc, and she received a 1099 instead of a W2 then she would have to file. They can't take the taxes out of those kind of jobs.
However if all her income had taxes automatically taken out, look here for information on the minimum wages required to file.
https://www.irs.gov/pub/irs-pdf/p501.pdf