If the internship is required by the school for her degree, or was at least organized by the school and she is getting degree credit for it, then it is "education" and not "work" (even though it probably felt like "work"). In that case it is taxable as other income (similar to a scholarship) and is not from self-employment. That means the income is taxable, but not subject to self-employment tax. She also can't deduct expenses. And she should not have a schedule C for this income.
There is a difference between internships that are simply lower paying entry-level jobs, and internships that are considered part of the student's education. We can talk about that further if you are interested.
