After 12 or in 12 you can attempt Nata it is held twice in a year. 

Some toys for Nata 

1. You can go for drawing classes to get good line drawing skills
2. Practice all the drawing situations given in previous year exams
3. Take a short term coaching before NATA / B.Arch..
4. For B.Arch paper2, study maths well. For B.Aarch, you should try to score full marks in aptitude, 60+ marks in drawing and if you score 20 marks, you can get in #1 institute SPA, Delhi
5. Expect slightly twisted questions for drawing.. For e.g, previous year question paper had “Platform view from window of a train” where as this year, the question was a view from the platform… You should know how to change the perspective…
6. Score well in 12th.. if you get 90% +, along with good NATA score, you will have tremendous choice…

All the best

Hello,

Yes in order to get admission through NATA you need to give exam in year 2020 after completion of your class 12. And to be eligible for this exam you need to score 50% marks with PCM as your subjects.

For more details regarding exam check below link.

https://engineering.careers360.com/articles/nata-eligibility-criteria