At least hree things have to happen before your heater will blow warm air: #1. The motor has to warm up, and warm up sufficiently to warm the fluid (the mix of anti-freeze & water) in your engine block to some pretty warm temperature, usually to above about 180 deg F. #2. There's a device called a thermostat that functions as a valve -- it has to open when the fluid temp exceeds 180 deg F or so. #3. Your water pump has to circulate the (now warm) fluid from your engine block into a part called the heater core (and elsewhere). If the thermostat doesn't open, the fluid won't circulate...at least it won't circulate well.
If it's, say, 30 deg F outside and then if you just start the car and let it idle, chances are it will take about 10 minutes, maybe 15 minutes of idling to get the motor warm, thermostat open, and fluid circulating. If you get in your car and drive it, it will heat up a lot faster, because you're burning more gas. My bet is if you get in it and drive it, the heater will blow warm air within about four minutes.
If you let the motor idle for 15 minutes or more and it's still not blowing warm air, then you've got a problem. With a car that's only 3 yrs old or so, though, that would be really surprising. If so, however, take it to your mechanic. It might even still be covered by the warranty.
