Hello aspirant

I hope that you are doing absolutely great

With reference to your above mentioned query, I would like to tell you that YES, you can change your class 12th from Hindi medium school to English medium School. This wouldn't affect your JEE MAINS preparation examination, but yes, in English medium you'll get extra resources nd will you'll be learning more advanced concepts for physics chemistry and mathematics.

So, you are absolutely free to change from your hindi medium to english medium school.

I hope that this wil help.