Dear Aarya, to be honest 90 seems a less score but you have fared better than 90 percentile of the students who wrote the exam along with you. If that is not something to be proud of, you can always appear for improvement exams. Now we are not sure what you want to study further, i.e. Engineering, Medicine, Commerce, etc. If your 11th marks will bear significance only until the relevant entrance exam like JEE, NEET, you neednt be worried. But if you plan on appearing for CAT, GMAT or go abroad where your marks will matter, you can appear for improvement exams. So decide your career path and then take a call.