Hey Aayushi.

CLAT is a competitive exam and starting preparation just 4 months prior may not be that effective. You can manage the topics like Legal Aptitude, Quantitative and verbal Reasoning, Math in 4 months. But you will be required to devote more time for GK and English Vocabulary. To prepare gor CLAT along with your 12th science boards, start reading the newspaper daily as you can not grasp a year long Current affairs just a few months before. Other than this you can take some hours out in a week and play daily quizes on Current affair On the website GK today.in. 

For rest of the section, you might be able to manage in the last 4 months if you work hard enough.

Best of luck!