OK, let's take the metaphor out. No more Apples & Oranges, we'll just talk Apples.
Mr. Dimwitt Flathead III walks into Apple store in February of 2008 and buys a NEW Mac Pro.
Right now, is that a 4 year old machine or a 6 year old one?
Assuming that it's the 1,1 Mac Pro, it's a 4-year old machine but a 6-year old model.
A teenager can be 13 to up to 19-years old. Different ages same "model".