Legal Question in Credit and Debt Law in Indiana

Yes you do, under various legal theories. You paid for a debt for which she was responsible, and you are entitled to be compensated for this payment. All you have to prove is that she was the actual borrower, and that you paid the debt, or part of the debt. There are different legal terms like "subrogation" and "indemnification," as well as "unjust enrichment" that are used to describe your position. You should speak with a lawyer and give more information about whether this person is actually collectible (able to pay a judgment if you win) before deciding what theory to proceed under.