Your little girl has a quite small ASD with 4.2mm.
Common symptoms for ASD include shortness of breath, swelling of the legs and lung infections. Most of these symptoms however are only seen in adults or with more severe ASD diameters.
Does your child show any symptoms of her ASD at the moment?
With 4.2mm her asd is quite small.
She will therefore most probably not have symptoms from it and so there will also be no visible signs for you that the hole has closed at a certain time.
There is a very good chance that the hole will close by itself in the coming months/years. It will take an echo doppler to see if or how far it is closed.