It will be an issue. I believe Keerthana is the original name in documents like Birth Certificate, Board Marks sheet and all. See you might face problem first when you will be entering the exam hall as they might check your Aadhar. With negotiations I believe it can be solved but the real problem comes during Counselling and document verification during college allotment. It solely depends on the college adminstration and other authorities responsible for document verification to clear you without hassle or not. At the worst of circumstances they may even cancel your admission. I believe you must be prepared to face a bit of hassle.