To become an IAS officer one has to crack the UPSC examinations which are considered as one of the toughest examination in all of our country.
First of all, UPSC occurs in 3 stages.
1. Preliminary examinations
2. Mains examination
3. Interview round
Preliminary examination are MCQ type and needs to be qualified to be able to sit for Mains which is a broad written paper. Final selection would be based on your Marks of the Maibs exam and Interview. Preliminary examination marks wouldn't be considered for final selections.
For being eligible to write the UPSC examinations one has to have a graduation degree in any subject from any recognized university. In my opinion, for people who want to pursue UPSC it is always better to take those subjects in graduation that would help you in your preparation of the UPSC examination. This isn't a necessity but just a suggestion. It's better to go for subjects like History, Geography, Political Science, Economics etc.
You can choose any of your interested subjects. A lot of doctors and lawyers, even engineers and bankers have successfully cracked the UPSC examinations. It is highly advisable to start your preparation from the first year of graduation itself. Start small, take one step at a time, clearing your basics first would be very helpful. For that, start with NCERTs of class VIII to XII of all major subjects like History, Geography, Political Science and Economics. Make a habit of the reading the newspaper daily, for this purpose, "The Hindu" is highly recommended.
After clearing your basics, move on to Indian Polity by Lakshmikant. Stay updated with current affairs and start reading the Yojana Magazines regularly.
Start taking help from Unacademy and Mrunal's blog.
Slowly build up the momentum of your studies and start solving previous years questions. Having regular practice of writing answers would increase your speed and vocabulary. Be sure to read good essays, usually, the columns of popular newspapers and try incorporating the writing style in your own way of writing essays.
Not just that, come up with strategies and be determined. A period of 2 years is said enough for preparing if the person is motivated and hardworking and dedicated.
Set small and achievable goals. Talk to seniors who are already training at LBSNAA. You can find them easily on Instagram and Facebook. Their insights would prove really helpful.
Hope this helps you.
The answer is any stream of your choice but as you are saying that what should I choose after 12 so seeing your dediaction towards this exams what you do is to go for Bachelor In Arts.
You can take majors Political science or sociology.
This subjects help one to crack any government exams like UPSC, SSC CGL and State Public Comission Exams and RRB too.
This subjects are very informative and easy to understand.
I will say if you belong from Arts background then please go for it but if you are from other background like Science, I will suggest that think twice or thrice or hundred times before changing streams.
UPSCs syllabus is unrecognizable and it changes with time.
I hope things are now clear to you.
According to me , BA is the best option. Let me tell you the reason behind it.
We know that UPSC exam is the toughest competitive exam in India. So, being quite frank , I must tell you that it is not at all easy to study for the exam along with the undergrad studies if the UG study is also tough. So , to put all the attention to clear UPSC you need easy subjects in college as no one can handle too much stress.
Hope this helps you.