It won't definitely fail, but the chances are high that it wll go sooner or later, and probably sooner. These belts have a lifespan, and when they're worn out, they need replacing.
Mines' a 2.8, and it's done 68,200. I got a quote from Whitehouse Audi in Bexley that came to just under £700, just for a new cambelt. The parts were about £150, the rest was all labour at £90 a hour, plus VAT.
It's going into to a good local independent a week today for a full service, cambelt change, MOT & front bumper respray. The parts cost will be the same, but they charge out at £40 per hour for labour (& £28 in the bodyshop). The whole bill will be about £800, of which roughly £400 or so will be the cambelt.
Do NOT put off getting yours done!!! If the cambelt did fail, a new engine would cost around £3,000.