That is really odd thing for your mom to say. I have to admit, I usually don't tell people to disobey their parents. However I am going to have to tell u to not listen to her. Hair should be washed every other day, to keep it clean. Yet u shouldn't wash it everyday. If u don't keep u hair clean, your hair is at risk of getting hair lice. Not a pretty picture. Now maybe if u hardly have any hair, maybe once a week is fine. But if u have quite a bit of hair, u need to wash it (at least 2 times in 1 week). I wish u all the best.