Tires Worn already?

[yaris2010RS]

so today i am sitting in my dealership getting my 32000km service. now since i had a dash issues before, my car only says i have 29xxxKm on it but in actuality it has close to 40,000km on it.

the service advisor just walked up to me and said my tires are warn. apparently the rear tires are warn down to the stops and the front tires do not have much to go before they reach their stops also. i have never done a tire rotation on the car so can someone please explain to me how the hell my rear tires wore out before my fronts? i can understand the fronts getting messed up, i have done quick accelerating and burnouts and squeels but i have never drifted on dry pavement (or even wet, i only drift on ice or snow and even then not much)

looking at my car i have always thought my rear wheels were angled in and my front pulls all over the road.....WTF!! lol, im so pissed off. he told me it will cost $482 for new tires, im assuming it would include instalation.

so basically im wondering if i should get my alignment checked and go from there to figure out how my tires got so warn or if i just need to suck it up as OEM tires wear poorly?

how long do most people get out of the OEM tires? i was hoping atleast 60xxx on them