You stated warranty but is the vehicle that new still? I mean brakes aren't part of the often touted powertrain warranty so you may no longer have the brake warranty, unless you were driving a lot of highway miles to rack up so many in a shorter period of time and in that case, it may not be due for a brake fluid change yet.
Otherwise if it is 3+ years old, I'd DIY, or in your case have a shop do it, primarily because it is listed as a maintenance item, and not a very expensive one, shopping around you can probably find a shop to do it for $100.