It is an odd part of photography marketing, but the bigger the print the more willing people are to call it art, pay more for it, and proudly hang it on their walls.

Having seen some of what you have posted here, this isn't the time to be shy about your work. It is definitely good enough.

Even though it is a friend's offer, it would be a good idea to write up some form of agreement between yourselves. Who knows, it is possible for a partnership with one taking the photos and the other putting in the office and marketing time. Have run across some who work it this way when they open their own store front.