You probably have a bit of haggle room since some around the nation are selling for as low as $15800 with similar mileage. Although, you live in CA where prices are higher so you may not be able to go much lower. Also, is this a private seller or a dealer? A private seller may be more willing to haggle, depending on how desperate they are to get rid of it (especially in these economic times
).
You may want to print out a couple of other used 09 Fits around the area that may be selling for a lower price, in case you want to use that as leverage.