Yes sorry Dakini is right, your car may not be due a service yet. Unless the service indicator is on. MINIs have variable servicing intervals and the car will decide when it needs a service based on how it is driven. When you turn the key in the ignition a mileage will be displayed briefly, before it changes to the actual mileage. This is the number of miles left until the next service. Check that first, if the service is overdue it will display a negative I believe.
The number you got by pressing the button will be the number of days until a brake fluid change
