You can definitely pursue a cause of action against your daughter for amongst other things Breach of Contract. The email that you have from your daughter is very important so ensure that you keep it in a safe place.
Due to the size of the loan you cannot file in small claims court and will have to pursue an action in the general civil division. While you are certainly capable of filing an action on your own, I would recommend that you hire a lawyer because of the complexities of the Defenses that your daughter may raise.
If you cosign a loan and end up paying for a benefit given to the co-debtor, you can sue for what you have to pay. Be careful, because you may be limited to when and how ofter you can sue. If the debt is not paid in full, talk to a lawyer first.
Mr. Goldstein is a Virginia-licensed attorney only. The information is not, nor is it intended to be, legal advice. You should consult an attorney for individual advice regarding your own situation. Answering this question does not in any way constitute legal representation. Contacting Mitchell Goldstein or the Goldstein Law Group does not constitute legal representation, nor is any information you provide protected by attorney-client privilege until otherwise advised.