I'm gonna complete my intermediate in 2020. When should I apply for 10+2 btech cadet entry?

Hello Dhupati Prudhvi Raju, For B.tech Cadet Entry Indian Navy has released the application form for 10+2 candidates on 29 November 2019. All the Unmarried male candidates are eligible to apply for filling the application for Indian Navy 10+2 B.Tech Entry Jul 2020. Whose candidates who will qualify will get a chance to do 4 year B.tech course under Cadet Entry Scheme.The shortlisting criteria of candidates are JEE Main 2019 All India Rank. Hence appearing for JEE Main is mandatory for the candidates.For the year 2020 the last date to apply was 19 December 2019.so, if you have not applied you have to wait for next year application.
Eligibility criteria are

Passed Senior Secondary Examination (10+2 Pattern) or its equivalent examinations from any Board with at least 70% aggregate marks in Physics, Chemistry and Mathematics (PCM) and at least 50% marks in English (either in Class X or Class XII).

Your Height should be at least 157cm with compatible to weight, and some restrictions for some categories.