There is NO lower age limit to apply for NATA 2019.
Candidates may come from the following backgrounds:
Passed 10+2 scheme of examination with 50% marks in Physics, Chemistry and Mathematics and also 50% marks in aggregate at 10+2 level examination; (those appearing the 10+2 exam with PCM subjects in the current year may also provisionally appear in the exam, however, their result in NATA-2019 will be declared valid subject to fulfilling the above criteria).
10+3 Diploma (any stream) passed/appearing recognized by Central/State Govt. with Mathematics as one of the subjects of examination
International Baccalaureate Diploma passed/appearing, after 10 years of Schooling with Mathematics as compulsory subject of examination.
NOTE: For more accurate & latest information kindly visit Council of Architecture official website