Peakey, dont stress mate, you are driving a German car, not a saxo or a corsa anymore, my A4 had 140k on it and it was still going strong, my mk3 Golf GTI had the same and my mk2 Golf GTI had 130k and just to top things off, my mate has a A4 1.9tdi with 240k on the clock with the original engine....still going strong.
As long as you look after it, you will have no worries......