A car should be fine to remap at any mileage (in theory!)
As the car goes up through the miles without remap, the parts that may fail get replaced naturally i.e. clutch, turbo, hoses, seals, exhaust, etc.
This is no different to a car on 80k miles or 140k.
See my old build thread for some of the mods and remap I carried out to my previous 140 TDI, at 80k miles all the way past 100k.