***** NOT A TEACHER *****
Hello, Selwan:
In my opinion, your English is very good for someone who has studied it for only three months. Keep up the good work!
I believe that there is a difference between "in case" and "in case of."
One book says that "in case" = If ("I'll be there in case you need me"); "in case of" = When there is ("In case of fire, break [the] glass").
That information comes from The Columbia Guide to Standard American English (1993) by Kenneth G. Wilson.
*****
Maybe your sentence should read something like:
"In case studying French does not interest you, you can always switch to English."
James