B.Sc Computer Science

For pursuing B.Sc in CS/IT you need science stream in your 12th without it you are not eligible for B.Sc because B.Sc CS includes maths, computer and physics as main subjects.

You can do even this by searching the institution on the google maps and later on for choosing the best one, you should take feedback from their past students and you can find out your needs by doing this. Thanks, don't forget to upvote. EDIT: Also, as Kanishk said you can visit such recommended institution and then take feedback.

Go for IITs as it's good for placement. Attempt for JEE.

You can try to specialise in bioinformatics, connectivity, gaming tech, cyber security, data analytics.

No need to have good marks. Placements only depend on your skills and knowledge like you are a good programmer then only you will get hired. Suppose, you don't like programming, but you are perfect in networking or designing field, you will get a job easily. In earlier days, the network engineering had a good demand in the market so take your choice and go ahead.

Top B.Sc. Computer Science (B.Sc. CS) Colleges in Dehradun are mentioned below:
1) Greenway Institute of Management Studies, Dehradun
2) Modern Institute of Technology, Rishikesh
3) DIT University, Dehradun
Regards.

You can pursue Master of fashion technology from NIFT. So, apply for the same.

If you have experience in any field, then it will not affect. You can easily pursue MCA.

Yes, it is possible to pursue ethical hacking course after B.Sc. Computer Science. Please check for your eligibility to pursue ethical hacking courses from the criteria mentioned below:
Eligibility: An ethical hacker must have a Bachelors degree in IT, CS CE etc. Or an advanced Diploma in network security. Besides the Bachelors degree, candidate should also have extensive experience in network security and a working knowledge of various operating systems. A working knowledge of the latest penetration software is essential. Regards.