Khushi,

CLAT syllabus is as follows:

English: There will be no more direct vocabulary questions

GK: Static GK will be removed and only your knowledge on current affairs will be tested

Mathematics: Only DI based questions.

Logical Reasoning: More emphasis on critical reasoning questions

Legal Aptitude: No Legal GK questions but the reasoning questions will remain.

If you look at the syllabus, you might have to only concentrate a little more in Legal Aptitude because if you are studying in ISC board, rest of the sections are quite easy for you. Do not drop a year before you know how good you are at cracking CLAT. We would suggest you to appear for the exam and then gauge your performance and then take a call. Meanwhile if you want to prepare for CLAT, this might help you: https://law.careers360.com/articles/how-prepare-for-clat-without-coaching