Manipal

Yes,
Sikkim Manipal offers full-time BBA course.
https://www.shiksha.com/bba/course/bachelor-of-business-administration-sikkim-manipal-institute-of-technology-sikkim-manipal-university-gangtok-249781

Don't go for private universities. You can apply for Government Universities, which have good scope and provide good knowledge base to you.

Hello Shubhra,
The two colleges that you mentioned have quite good reputation. I suggest you select the one that is convenient to you.

Kindly visit the link mentioned below:
https://manipal.edu/mit/programs/program-list/mtech.html

VIT is better followed by Manipal and then Thapar. Since this college has the best of placement, infrastructure, education, opportunities and exposure to the real world. Though VIT and Manipal are almost the same in all the above terms and these two are better than Thapar.

12th marks are only required for being eligible to give the entrance tests of the institutes. For BITS, it is aggregate 75 % in physics, chemistry, and maths with 60 % and above in each subject. But for a general perspective, a higher percentage in 12th certainly enhances your opportunities and chances throughout your career.