Hello Achu, 

Look there are lot opportunities for girls in navy. Initially, girls were not allowed in the aviation branch but now Indian navy, as well as Indian air force, also allowed girls to fly fighter jets. Now there are different entries through which you can get into Indian navy. 

Since NDA is currently only for boys. So girls need to get graduation degree first to get into Indian navy. Now if you want to get into engineering branch or technical branch of the Indian Navy, You need graduation in Mechanical or Electronic engineering. After that, you can apply for CDS exam. Other than this you can also apply for UES(University entry scheme). 

Beside this, girls are also allowed in an Educational branch of Indian navy. For this either you need graduation in Mechanical or Electronic engineering or BSC from any subjects. You can also join Metrological Department of the  Indian Navy.  

For more information, you can visit the official website of Indian Navy. The link is provided below.

https://www.joinindiannavy.gov.in/

Hope you find this information useful. Have a great future ahead.