Class 12-science

If you want to take admission in dietetics after class 12th, then you should choose physics chemistry and biology as your main subjects. With PCB, you will be eligible to write the NEET exam also.
Best of luck.

Hi, do not worry. There are several colleges in India those offer B.Sc in Mathematics. You can refer the following link:
https://www.shiksha.com/science/colleges/b-sc-mathematics-colleges-india. These are some of the colleges in Gujarat:
MSU Baroda
Wisdom School of Management
Parul University
M. G. Science Institute
Rai University
Ganpat University
St. Xavier's College
Gokul Science and Commerce College
Good luck.

I suggest you to follow the link to get all the details to get admissions in this college
https://www.shiksha.com/college/amrapali-group-of-institutes-haldwani-24855

If optional have Biology then
1 MBBS (Bachelor of Medicine, Bachelor of Surgery)
2 Veterinary Sciences
3 BAMS (Bachelor of Ayurveda, Medicine and Surgery)
4 BDS (Bachelor of Dental Surgery)
5 Pharmacy.

Hello,
You must pass the entrance tests conducted by the respective institutions or the common entrance test conducted to pursue B.Arch i.e. NATA National Aptitude Test in Architecture. I. Student must have scored minimum 50% aggregate marks in board examination from a recognized education board. The minimum score range may vary from one institution to other. Ii. The age must be below 21 years. Iii. The admission process is mostly based on the score from the entrance test. The merit based admission is granted for deserving students. The Architecture career is now made available for the students who had taken Arts as there in +2.

There are so many options like MBBS (Bachelor of Medical and Bachelor of surgery), BHMS (Bachelor of Homeopathic Medicine & Surgery), BA MS (Bachelor of Ayurveda Medicine & surgery), B.Sc Agriculture, B.Sc Zoology, B.Biotechnology, BE in Man Made Fiber Technology, Microbiology etc.

Yes, you can study.

If you interested in Medical field then go for the preparation of NEET and other state exams. Otherwise, go for B.Sc.

Yes, you can apply for BCA as you have completed class 12th.

It's average score. Since ICSE paper setting and correction are very liberal, 82% is just an average score. When my daughter completed class 10th in 2014, around 70% of students scored above 80% in her school.
Any way you can always work hard and do much better in your future exams.