Hi Raghav ! UPSC has got a vast syllabus ,but basics are always important . I would advise you to study sincerely whatever is there in course . But don't sweat it. Just cover the syllabus in your course properly.

During the final year of graduation , you can start preparing for the exam in a structured manner. Now if your basics are strong , it would prove to be the brownie  point for you , as you would only have to brush them up , and focus on learning the new content more.
Hope my answer would clear your doubt.

Hello Raghav,

You'll be able to write the UPSC exam after your graduation. If you wish you can study small topics in school. However you'll get enough time in the first two years of your college to prepare for UPSC. And students dedicate themselves to the preparation in final year. So even if you don't study now you'll have plenty of time to study it in college. If you start the study from school you'll have continuation of the subjects.