There is a good discussion on this subject on Quora

Is it okay to do Computer Science in university with no prior computer science knowledge?

https://www.quora.com/Is-it-okay-to-do-Computer-Science-in-university-with-no-prior-computer-science-knowledge

About a third of computer science majors at Illinois (ranked comfortably in the top 10 in the US) start with no programming experience. By the end of the second semester, it is no longer possible to tell which students started with no programming experience and which ones started programming in the womb.

As far as I can tell, pre-college programming experience has absolutely no effect, either positive or negative, on students’ likelihood of success as a computer science major.

 

--- By Jeff Erickson,

CS professor, University of Illinois Urbana-Champaign