Sure dear Ashutosh you can be prepared for UPSC  from now but you have to know about the eligibility criteria for UPSC that is - you have a graduation degree from recognised college/university in any stream.

Well prepared for your 12th and simultaneously prepared for UPSC, failure is temporary, do your hard work you can achieve your target by hard work, practise and patience. Be motivated.

All the best dear

Hi Ashutosh!!! UPSC is an exam which should be given after graduation as the minimum degree required is graduation. So, I would suggest you to concentrate on your boards now and then on admission to your desired college and 1-1.5 years prior to your graduation ,you can start off with the preparations. All the best for everything.

Hope that helped.Thank you.