I saw this on "Detailing World" and quite liked the idea.
1)Take the mileage on the car's odometer
2)Divide by the model year
The result is your car's age if it were a person
So to start you off:
Mine is a 2003 Vectra GSi with 113,000 miles.
so 113,000 divided by 2003 makes my car.........
54 years old!