It sounds like your mother took out the loan, not "Mom and I." As I understand it, on a Parent Plus loan the parent is the borrower, not the child. One of the requirements for claiming the student loan interest deduction is that you must be legally obligated to pay the interest. You are not legally obligated to pay it. You mother is. So you cannot deduct the interest. But when you make the payments, it is treated as if you gave the money to your mother and she made the payments. So your mother can claim the student load interest deduction even though you made the payments on her behalf and she didn't actually pay the interest herself.
