An Indiana woman convicted in a crash that killed three children who were crossing a highway to board a school bus is appealing her conviction, contending that the tragedy was “just an accident and not a crime,” her attorney said Tuesday. A notice of appeal was filed Jan. 17 with the Indiana Court of Appeals on behalf of Alyssa Shepherd, 25, of Rochester. Stacy Uliana, the attorney representing Shepherd, said a brief that will include the arguments in her client’s appeal will not be filed for months.