Hello Aspirant,

Thanks for contacting Careers360.

No, it's not necessary. You can do Computer engineering without having computer science subject in class 12th. Whatever you will get to learn in Btech / BE that does not need any prerequisites or CS background, but yes if you read CS in your 11th and 12th standards, it will definitely clear your doubts earlier than a non-CS student. Otherwise you can take whatever you want. My suggestion would be that if you are thinking for choosing Computer Engineering and if you are having keen interest on this subject , then just go for it from the very beginning of your career. 

Hope this helps. Good luck!