Then people would choose skinny body type with 10 Strenght. Makes no sense. But if your body type changed by the amount of Strenght points you have, that would be swell
That's there choice to make, I wouldn't want my character's appearance to be determined by my stats as I want to create a character that looks the way I want, and play a character with the stats and abilities I want to use, if I don't appearance to reflect my stats, that should be my choice, if you want to create characters that look as strong as they are, you could just, oh, I don't know, choose the appropriate body type, as long as the choice is there, it's pretty easy.
But I'd imagine that age will be handled lik in Oblivion, in other words, when creating your character, you'll also have an age slider when choosing your facial appearance, where you place it determines how old your character looks, so most likely, age is purely cosmetic and won't change anything about gameplay.