It's totally depends on you. If you are determined to get into top NITs then you can prepare for JEE Main exam. Make sure you prepare well for your exam. Make your basics strong. Learn from your past mistakes. Focus on the important topics. Solve as many as MCQs for your preparation. You should also solve complete mock test series to analyze your preparation level and to know your weak and strong areas. So, you can work upon them.

All the Best!!