I personally would go with the new bow. Since you are new to the sport, the nuances between the two models likely will make little practical difference as long as you buy a bow that fits and receive some good initial shooting instruction & advice.

In addition, you will be getting the knowledge and experience of the Pro-shop to help you out both not only at the sale but in the future(assuming you are buying the used model elsewhere), and any warranty problems you may have with the bow will be covered.