Depends on the reader and how well he or she can comprehend things like gear ratios, hill grades, electronic logs, etc..... If you were an accountant looking for a career change, it might be hard for you.
From what I hear, the written part of the CDL test isn't too difficult to pass. Just study the CDL manual thoroughly, and you should be okay. You can take a practice test online if that makes you feel better, too.