question is not whether one would have some memory in the age of 4 (such as the memorizing a phone number/list of words), but the question is whether a genuine memory formed at the age of 4 can last untill 16 or 17..
If she is having such and such psychological troubles like post traumatic stress and panic attacks, ( I belive this may not be the case since there is a big time duration) focus on treating them at the first place.