Job Interview

This morning I am attending a job interview. I have worked in one industry for the last 10 years so when I have changed my employment from time to time it was from one dealer to another doing the same thing.
So this should be interesting as it is unrelated to previous roles. It does have some similarities and the aim is the same, selling. I have been told that the interview consists of two written assessments and the second part will be an interview using competency based questions, whatever they are? I am old school and sometimes have difficulty understanding modern interview methods but I understand that there is a necessity for processed interviews as some conformity is required for comparative standards. I of course believe that a simple conversation with a potential candidate is sufficient to assess whether a potential employee is suitable.
Perhaps this stems from the premise that I am almost 60 and therefore have been there seen and done it. I have experience and a perspective that obviously only someone of my age would have. If your a much younger candidate going in to this process perhaps a standard is required in order to provide a level playing field.
I will soon find out but I confess I have some trepidation about the process and whilst I am not nervous, it maybe that this form of interview may not suit me? We shall see!