Hello,  according to news,

"Girls may soon be allowed to take admission at Sainik schools and National Defence Academy (NDA). The government is considering to implement such a proposal, Union Minister Subhash Ramrao Bhamre told the Lok Sabha today ."

But this is only decision and this proposal is in lok sabha now.  So there are chances,  we can not say perfectly now,  but you can start preparing. Because study is  always useful.

I hope it will help you.

thanks.