When you're in your twenties, you most likely want the girl who is an absolute freak behind closed (elevator) doors. You want exhilaration and some crazy memories that will make you snicker every time you think of them. This girl is an Ariel Atom 500, nothing but fun, all the time ... unless it's raining, or there's a speed limit, or you can't afford more tires.
Once you hit middle age, you'll still be wanting to have some fun, but not at the expense of the crap that you actually need to get done, and you aren't willing to risk your life for it. This woman is a Mercedes-Benz E63 AMG Wagon, the ultimate family man's sporting car.
An old guy just wants comfort and dependability. This woman is a Bentley Mulsanne.