The question has not provided many necessary details. In which stream did you study in X+II? The answer mainly depends on this. Furthermore, what is your own aim? Have you taken admission so far? If yes, then with which combination? What about your parents' opinion?
At the outset, I must state that one single examination can't determine the calibre of a student. If you have determination and inclination, you can shine during and after your Graduation from any university. Furthermore, if you want to be employed quickly, then after Graduation, you can appear in various competitive examinations. As you are very young, I suggest you to make an attempt for NDA examination conducted by UPSC for joining commissioned rank. The eligibility is X+II. You can also attempt CDS examination conducted by UPSC after Graduation. But this course of life is preferable only if you are inclined to join armed forces.
Personally I am dead against 'dropping' and wasting a valuable year.
You can seek guidance from the Members of ISC giving further details.
Caution: Explosive. Handle with care.