Can't answer specifically for Audi , but I can say driving conditions and habits (some forced, due to other peoples driving) can shorten the lifespan dramatically. I work at a Honda dealership and saturday I inspected 2 2013 4Cyl. Accords , one had 32K on it and the right front outboard pad was at 1/32" , the other Accord had 33K on it and still had better than 7/32" on the thinnest area of pad (about 2/3 of original pad thickness). First was all beltway(D.C. area) traffic jams , the other was highway mostly. How many miles does yours have?
I'd say that's a bit early , unless it's all stop-and-go rush hour traffic. Hopefully you had the work done at the dealer , in case there is any kind of warranty or service bulletin that comes out and will reimburse you. Like I said in my first reply , I know Hondas' , and they have had a few issues similar to yours and once they had enough 'data'(complaints) on record to prove the issue , they came out with either repair procedures or reimbursement plans for owners that already had documented repairs done.