Lefties quite literally come at the world from a different angle. If they do not receive the appropriate supports, it could affect the neatness of their writing, their self-confidence and their motor skill development. Keep in mind that hand dominance does not fully develop until five or six years old. While a child who writes with the right hand tends to do everything with the right hand, it is common for children who write with the left hand to do varying activities such as throwing or eating with the right hand.