As you're going to persue B.Tech in future, It'll be really good for you to choose CS over Hindi. You've to go through the "computer programming" in your 1st or 2nd semester no matter in which IIT or NIT you'll be. It's quite nessesary to have a good knowledge in CS for any Engineering student.
•Considering the recent situation, if you're choosing Hindi, then you've a vast area to cover as it's syllabus. Basically it's a language and so, you're expected to have particular grammatical idea, writting skills in this language.
•But CS in schooling level is just an introduction to CS. It's limited and precised course. It will provide you the basic idea that gonna help you out during your college.
From my perspective same effort is required for both of the subjects. But CS has it's own value in your future. So choosing CS over Hindi should be preferable for you. Jee preparation will not be affected for this at all.
All the best for your JEE.