i have a baby sister and she is four like your daughter, i am 16 with a mild stutter and i started stuttering at around her age so i think its genetic i think it depends where the stutter has came from and what the cause is, as for some people it just happens for a short amount of time for their life, unlike me i have been to speech therapy at the age of around 7-8 and it has not done much for me but give me techniques on how to slow my speech one tip that may your daughter help that helped me is to speak slower, as i find that sometimes my family and i speak so fast it ends up in me being caught up in my words and trying to blurt everything out overall stuttering is not a major issue in my life, i would say im liked and popular in a way so stuttering has no negative impact on social life, mentally i do fear talking to strangers such as when i have to order things no one is perfect though and everyone has a flaw and maybe stuttering happens to be your daughters, but dont loose hope go to a speech therapist and see what they say:)