I agree that would be a good price in California.
Hmm... depends on some specifics... complexity of roof/installation, whether this includes a Hybrid Inverter (for ease of adding future batteries) or not, etc.
For original poster: A significant portion of cost is the design, labor for permitting, and basic wiring for PV system. Whether 20 or 33 panels, extra price for additional panels is marginal (cost per panel, and a bit of labor/other)... for the most part. ie, $/kW should go down as system size increases (to a point). Here is SoCal, when I looked 18 months ago, that quote would have been definitely on the high side (to point of being ignored) for a simple 33-panel system (no hybrid inverter, single flat roof surface for all panels, etc) from a vendor with a very comprehensive warranty. But many factors can drive up price (like main load center service upgrade)... so it depends
Considering system life, I'd advise making sure installer is fully certified with panel manufacturer, such that you get a full system output guarantee from panel mfg. If in 20 years, the idea of you going up onto roof to take pictures (ex. Panasonic warranty I came across) isn't a pleasant thought, make sure warranty includes vendor doing the troubleshooting onsite. And then, there will be other components, like inverter (micro, string, or ??)... the thing to look for is system output to avoid finger-pointing at some future point about why system not producing power, or really low, etc. Such warranties do exist... whether worth it to you or not?? for me price premium for installer with much better warranty was small enough to make decision easy