Icse — Why so less time for competitive exams and

I am a student of class 12 and appearing for board exam this year .I have very simple mathematics calculation to show to the board authority.According to board, they want student to give this semister I exam and it will end on December.Again prepare for pre board held by the school.And again prepare for board exam in March which will go till April.And again prepare for competitive exam.Why so "prepare " prepare ...