Hey Pratibha

To be eligible for Combined Defense Services (CDS) you need to have completed your degree from a recognized degree, and with a reappear in your second year you might not get your degree completed and hence won't be eligible for CDS.

You can attempt CDS until 25 years of age, and once your graduation is complete you can definitely apply for the same in Officers Training Academy (OTA - Women, Non-Technical) . So you may finish your graduation and apply for CDS soon after that.

For further doubts, ask us. All the best