Hello,

Eligibility criteria for NID is :

• 10+2 with any recognised school
• Intermediate or two-year pre-university examination under a board or university recognised by the Association of Indian Universities (AIU).
• Final examination of the two-year course of the Joint Services Wing of the National Defence Academy.
• Upper age limit for candidates is 20 years as on 30 June 2021. Only those candidates born on or after July 1, 2020, are eligible to apply for admission in general category
• For other categories Upper age limit for candidates is 23 years as on 30 June 2021. Only those candidates born on or after July 1, 1997, are eligible to apply for admission.

exam is conducted in the month of January, each year.

You can refer to this link for more details about NID

https://design.careers360.com/articles/nid-dat-eligibility-criteria

Hope this helps!!