Hi dear
There's no problem at all if you don't know any programming language before joining the course.
In the course, you will be taught the required languages from basics.Once you join the course, you can take side by side coachings for some specific languages if you face any difficulty.
I am also a student of b.tech cse and i knew only java (10th level) before joining the course.I have completed my 1st year and studied python in the 2nd semester, I too wasn't having prior knowledge about python but now I am good at it.Some of my friends didn't even know anything about programming but now they are good at it.It all requires hardwork, interest and dedication.
So, if you are interested in cse ,go for it .
For prior knowledge, you can get help from youtube.

Feel free to ask any query in the comment section.

Best of Luck!!