Resolved Question: Worried about past work history affecting if I get this job?

I applied for a court clerk position at a circuit court about a week ago and have been called in to interview for it in a few days. The requirements of this position were that you had to have 4 years of experience working in legal setting (full time and paid), clerical work experience, knowledge of the court system and Probate. I am worried if my past work experience might effect me getting the position. The reason I say this is because I currently help out my cousin (who is an attorney) at her firm one day a week all day as a legal secretary. She cannot afford a full-time worker so she has me one day a week (unpaid) and a part-time secretary. I have gained a lot of experience from this position (been there 4 years now) even though I have been working only one day a week. I am familiar with the way the courts work and the forms, scheduling and adjourning, etc. The educational requirements for this job is just a high school diploma and I carry a bachelor’s degree and also speak an additional language fluently (English is my 1st language). I am afraid if I tell the person interviewing me this, they might think I lack experience even though I do not. And I am also afraid to even keep quiet about me helping out and acting as if this were a fulltime position in case they do a background check. I know they verify your work history but do you think if they called my cousin and she said she volunteers here one day a week, that this will affect me not getting the position???? I really want this job more than anything right now. I do not know what to think. What are some of your opinions and how should I handle the interview when asked about work experience???