Do I need AC service?
 

I bought a used 2010 Civic, so I don't know how it operated when new.
I noticed that when using the AC after the car has been in the shade, it cools reasonably well. However, if it was parked in the sun, it takes a long while until it feels really cool, especially when driving around town. I also noticed that the radiator fan will turn on at the stop light and stay on for 95% of the time while the car is standing. If I compare this to other vehicles, I do find that the Civic's fan is on for more time and turns on almost immediately when arriving at the stop light.
When driving on the highway, it seems to be working reasonably well. Our local weather is pretty mild, 80~90 F when the AC is on.

Also, when the car was parked in the sun, but the temps are pleasant (e.g. 70), if I turn the (cabin) fan on but keep the AC off, it feels like it blows slightly heated air for a long while, even if the knob is turned all the way to the left. This does not happen if the car was parked in the shade.

Is this what I should expect?

it mite be low on refrigerant,does your state allow you to recharge yourself. if so you can easily do it yourself for $35 bucks with a kit from walmart. turning on the the fan will be warmer yes because the air is passing over the hot engine.