You first have to complete your graduation now since MCS is a masters degree ie post graduation course and you can pursue it once you finish your graduation. You can choose Bsc or engineering in some field that you like now from a decent college with your 12th board marks or any other competitive entrance exam marks and then can choose the same field for pursuing masters degree (MSC).

Refer to the site below to know more about the same...

https://www.careers360.com/courses/msc-master-of-science

Best wishes. Thank you.