Hello Deepa,
Hope you're doing great and it's good to see that you're clear about what you want in your life at such an early age but you should know that UPSC is one of the toughest exams in India and minimum eligibility criteria for it is graduation so for now I'd advise you to opt for whichever stream you find interesting. Side by side you can keep on looking the UPSC syllabus and read as much as you can. As UPSC paper consists of an optional paper so you can complete your graduation and then decide which subject you'll opt for it. Currently I'd advise you to go for subjects and stream you have interest in.
Please find attached the syllabus of UPSC examination.
https://competition.careers360.com/articles/upsc-ias-syllabus/amp Good luck!
Result | Eligibility | Answer Key | Cutoff | Selection Process | Preparation Tips | Application
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile