Dear Pavan,

In real it is difficult but you can .So according from Commerce or CA background to Information technology  it will difficult but you can start your journey of ethical hacking .Ethical hacking is basically  based on Programming , Encryption and decryption of data ,Networking and Data Base.

So for you better start  from entry level , you must know some knowledge of programming because in ethical hacking most of advance programming is used , so without basic knowledge we cant go for advance level .you start basic knowledge of programming like c,java ,c++,Linux ,Then only go for any kind of ethical hacking course like diploma course or any type ethical hacking certificate course .

But become an Ethical Hacker you must depth knowledge of Computer science and advance Architecture of Computer.Only Certificate holders cant be a good Ethical hacker ,so you must practice on it and good knowledge in programming with certificate then only you become an ethical hacker .

I hope it will helpful and best of luck for your future .

Thanks