If you want to go for the Quantum Computing, there is no direct course after 12th. You can participate in Quantum Computing in two pathways. The first pathway is that you go for technology background such as BTech CSE, CSE with specialization in Data Science & ML, ECE etc. After that you can join internship in Quantum Computing companies and can learn the stuff and learn about it.

Apart from this there is Quantum Computing India, a government recognized program which you can do after your graduation. For that you can go from Science as well as BTech background.

Also if you go for BSc and MSc Physics then also you can join Quantum Computing research and can become a researcher or lead scientist in the field.

For more information regarding Quantum Computing Certification programs (online), you can consider the link below:

https://www.careers360.com/courses-certifications/quantum-computing-courses-brpg

For more information regarding Quantum Computing India consider the link provided below:

https://quantumcomputingindia.com/

I hope this helps. Wish you a great eve!