I'm gonna give you a conflicting answer. If she was enrolled half time or more, for any period of time, she is eligible for a tuition credit, if she actually paid tuition (and not had it paid by tax free scholarships). The fact that she is paying back the scholarship has converted the scholarship to a loan. That means that any tuition paid was paid by her funds.
It may be her age that is disqualifying her from the credit. A full time unmarried student, under age 24, is only eligible for the refundable portion of the American Opportunity Credit if he supports himself by working. She cannot be supporting herself on parental support, 529 plans or student loans & grants. She must have actually paid (loans count) tuition, not had it paid by scholarships & grants.
But if she is disqualified from the credit, she may still qualify as your dependent, if she was a full time student for parts of 5 calendar months (e.g. Jan 31 to May 1 counts as 5 months) and was under 24.
