There is no age limit for NATA architecture course at all. 

ABOUT NATA

National aptitude test in Architecture (NATA) which is the entrance exam for B. Arch course in various Indian colleges or universities at national level. NATA is conducted by National Institute of advanced studies in architecture (NIASA) the body of council of Architecture in India. This entrance exam is a national level examination. Students who are willing to study Bachelor of architecture or some other relevant architecture courses at all recognized institutions across India, can give NATA after their 12th examination.

ELIGIBILITY CRITERIA FOR NATA

NATA Eligibility Criteria is divided into 4 sections such as age, qualification, subject, minimum marks. The candidates must be eligible for all the 4 sections in order to qualify NATA. 

• Age- Fortunately, there is no age limit now to qualify NATA. 
• Qualification- Qualifying 10+2 examination in with the subjects Physics Chemistry maths from any recognized board is must for the candidates. Or candidates who have qualified 10+3 with mathematics from any recognized board can also eligible for NATA. 
• Subject- The candidates must have Physics, chemistry and mathematics as a mandatory subjects to be eligible for NATA. candidates from arts stream can be eligible too only if they are qualified the physics, chemistry and mathematics exams conducted by CBSC
• Marks- The candidates must score minimum of 50% marks in their qualifying examination and 50% marks in Physics, chemistry and maths. 5% relaxation has been given to SC, ST, OBC-NCL category or PwD candidates. 

NATA SYLLABUS

NATA measures drawing and observation skills, sense of proportion, aesthetic sensitivity and critical thinking ability by 2parted exams.
first part- paper based drawing test
second part- online test with MCQs on Physics, Chemistry, Mathematics and General Aptitude Test. 

1.Drawing includes memory drawing, shades, shadows, 2D compositions, visualisation, perspective drawing etc.

2. Aptitude test includes Diagrammatic Reasoning, Numerical Reasoning, Verbal Reasoning, Inductive Reasoning, Situational Judgment, Logical Reasoning, Abstract Reasoning. 

3. Mathematics include algebra, logarithm, matrices, trigonometry, coordinate geometry, 3D coordination of geometry, theory of calculus, application of calculus, permutation and combination, statistics and probability.

4. NATA also includes questions from Physics and chemistry in which class 10-12 studies are important. As well as includes general aptitude test with mathematical reasoning, sets and relations. 

Hope this helps!