Hello,
If you didn't have Computer science as a subject in your class 12 and in college you have opted for CSE then you need not worry, in your college you'll be taught how to do programming from the very basics. There is no requirement whatsoever.
Although if you want to ace your classes from the very start you can do an online course on C/C++. This will give you a Basic idea on programming and somewhat a headstart. You can also do a course on python since it's in very demand these days.
The students who had computer science as a subject in class 12 will have a slight edge over you but you can keep up with them in the long run. So you don't have to worry about not having knowledge about the subject.
Hope this helps
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile