CBSE 12th

You are not eligible to do Automobile Engineering because of your Humanities background. You are eligible to do BCA and become ethical hacker.
Ethical hackers are specialised Cyber Security experts who work for all organizations which have an internet presence and use extensive use of web technologies for Business . Ethical Hackers role is a proactive one as they prevent cyber- crimes and protect cyber space from intrusion. They ensure data security and protect computer systems from illegal hacking activities. Computer Hackers use their expertise in computing and knowledge of programming, web applications, operating systems, assembly language, internet security systems etc. to protect computer systems from illegal hackers.
It is a niche skill and has limited career opportunities. However, if you able to break into your first job then its is very high paying and respected job. Most of computer hackers have graduation degrees such as BTech CSE/IT, BCA-MCA, BSc CS. Most of the hackers are those who have excellent programming skills.
You can appear in professional certification examination to become a Certified Ethical Hacker (CEH) by appearing in examination conducted by ED-Council. Certification is achieved by taking the CEH examination after having either attended training at an Accredited Training Center (ATC) or completed through self-study. CEH is a skilled professional who understands and knows how to look for weaknesses and vulnerabilities in target systems and uses the same knowledge and tools as a malicious hacker, but in a lawful and legitimate manner to assess the security posture of a target system(s). The CEH credential certifies individuals in the specific network security discipline of Ethical Hacking from a vendor-neutral perspective.

For law, you may choose UK or USA and start your preparation accordingly. English Law, or common law, is the basis for many legal systems, including those in Canada, Australia, New Zealand, Singapore, Malaysia, India and Pakistan. An international law degree is a great asset in the global economy of today as many business deals are negotiated across borders.
Although the USA also uses common law, it offers a different style of legal study. In the US, you can study a JD (Judicial Degree), your first law degree, and then progress to an LLM (Masters of Law) as a graduate.
For USA, you need to appear for SAT and TOEFL/ IELTS. Choose universities as per your grade, budget and specialisation.