Most of the time I use expressions such as 

> 
> O meu cabelo está a ficar muito grande.
> 
> 
> 

Instead of **grande** one can use **comprido** or **longo**. Now, in the english language, saying

> 
> My hair is getting too big.
> 
> 
> 

is incorrect (as far as I know). Instead, one must use **too long**.

My question is then: to what extent is using **grande/pequeno** for hair, as correct as using **longo/curto**? The words long/short are used for things that are measured by length, which hair is an example of. Am I then using the Portuguese words incorrectly?