Hi aspirants

Yes you can do UPSC preparation after BSC. Main requirement of UPSC is that you have a graduation degree in any course and you should also clear the age criteria

Age limit as per UPSC Notification 2021

A candidate must have attained the age of 21 years and must not have attained the age of 32 years on 1st August 2021. This means the candidate must have been born not earlier than 2nd August 1989 and not later than 1st August 2000.

Hope this Helps

Good Luck!