Many institutes require a minimum of 60% in Class 12th PCM (Physics, Chemistry, Mathematics). Since your aggregate is 58%, you may not meet the standard eligibility criteria for many programs such as the IMU CET (Indian Maritime University Common Entrance Test) in India.but what you can do is to go for direct admission offered by many institutions Some institutes may offer diploma courses like Tolani Maritime Institute you can join or if you want to appear for IMU CET go for improvement exam.all the best