one can start preparing for UPSC after 12th. No specific degree is required for the UPSC exam, but some degrees can be helpful in preparation like political science, humanities , sociology,public administration, economics these subjects courses are available in universities after 12th for bachelor degree you can pursue.
One thing you should remember that Whatever optional subjects are to be taken in the UPSC exam, the same subjects should be studied in graduation
Additionally,Stick to NCERT books,pyq papers all are important for UPSC.take guidance if required once you entered in the course you will get to know UPSC exams better.
Final words,its a tough exam so be prepared for it mentally and persistence is the key for the exam never give up attitude requires if you are ready go for it..
All the best for future
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