CBSE

Please go with this college predictor. This will help you to choose the best college-
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
Thank you

Check for colleges which you think you are eligible to apply in Shiksha college section page. Upon eligibility, go to that college official website and fill-in online application or visit the campus and fill offline application if available. With this rank, you can get admission in some government colleges, but not possible for you to get admission in NITs.

12 is the source code in TNEA form for CBSE 12th passed student.

Hi,
If you have not appeared in GUJCET 2019 then you can secure admission through direct private management quota.

Hi,
Yes, 122 a is good score in NATA exams. Government colleges would be difficult, but surely you can secure private colleges. With 122/200 Marks in NATA 2019 exams and 82% score in your class 12th, you have chances to secure admission in very good colleges across the country. It would have been easier if you could have stated the state/ region, you are seeking to pursue your B.Arch programme. Check the link below to get a list of approved architecture colleges.
https://www.coa.gov.in/index1.php?lang=1&level=0&linkid=25&lid=26.

Yes, you can get admission in BSc maths with this percentage.

Yes, you can get admission here. Your percentage is good. You should apply for the admission.

Yes, you are eligible for NIFT exam. You can apply for this exam.