Probably not. The first $5250 of employer educational assistance is usually tax free. If you got more, and it was included in your taxable income (this should be reflected on your w-2), that part is considered your money and can be used to claim the credit.
The American Opportunity Credit is only available for undergrad courses. You would have to claim the Lifetime Learning Credit, if she is a grad student (and the tuition was more than $5250)
