Cant update new Wii U

I just pulled my new Wii U out of the box and plugged it in, im still in the setup part at the adding a new Nintendo Network ID or linking one you already have, I click the link one I already have option because I do have one then it tells me I need to do a system update to do that and restarts this setup section.  Do I really have to make a new one and if I do can I change it back to my real one once I update?