This question is similar to the famous 'Tell us about yourself' question. Were you drawn to this agencies description because you felt it was written just for you? Is the description something out of your comfort zone and you're ready for the challenge? Be confident with your answer. Don't talk yourself out of the job by stating you don't have the experience. Secure the job by showing your enthusiasm, confirming your capabilities through your education and skills and let the interviewer know that you are a new set of eyes ready for the challenge.

"When I read your job announcement I knew I had to apply, I felt like it was written just for me! I've had the opportunity through my experience to match up to all of your qualifications and then some! I'm excited for the opportunity to share my experience with co-workers and pick up where I left off with new clients."