Hello Isha

So as you mentioned that you are in 11th and your 11th class session will end up in 2023. With this your 12th class session will also begin in 2023.

You must be aware that NDA is conducted twice in a year. So according to this the t otal number of attempts which you can give are 4.

One will in your 12th during September.

Others will be in 2024 during April and September.

And for 2025 you have only 1attempt which falls in the month of April.

But after that you can't give NDA as by the time you will exceed the  maximum age (19.5 years ) criteria.

So buckle up and all the best.

Hoped it would have helped you.