You should see a speech therapist, they'll know what's best for her. You can't expect her to grow out of it, it's like thinking that a blind person will eventually be able to see again, it's not the same but you get what i mean. If she stutters it doesn't mean she'll accept it or it won't define her, stuttering changes people, and not necessarily for the better. Also she'll have problems with social interactions, finding a job and basically any simple thing that involves speaking, I wouldn't be so calm on this, trust me, go see a speech therapist, they might help her handle it