you can give national defence acadamy examination which will conduct twice in a year.You have to have a science group in your higher secondary examination.you can get the related sample books from the bookstall,there you have to study for three years in between there you have a logical test according to test you will be putted in selected field.

no

yes there are many schemes for women to join the indian army after the 12th .if you have passed your 12th from science stream there are a direct entery through the TES