CoC ChemBio Undergraduate's Chances of Changing Majors to Computer Science

I am currently an undergrad at UC Berkeley in the chemical biology major and I was wondering how difficult it would be to change majors to Computer Science. Thank you.

EECS: 0%, since change of college is not accepted into EECS.

L&S CS: can you earn a 2.50 GPA to change into L&S, and a 3.30 GPA in CS 61A, 61B, 70 to declare the L&S CS major?

So a transfer of college to L&S CS can start right after the first semester as a freshman if you have the other requirements ready? Also, will changing colleges put me behind everyone else and should I try to take classes that are relevant to CS beforehand as a freshman? Thank you so much for your help! Please stay safe.