The long summer break came to an abrupt end for thousands of San Angelo I.S.D. students Monday. Exactly 13,563 students headed back to class. According to school administrators, the months of preparation for the start of the new school year paid off. School leaders say the first day of school was nearly flawless. In addition to students, more than 2,000 San Angelo I.S.D. employees also returned to work for the first day of class.