Surgery for Adenoids is done when there are infections in throat which occur again and again, there is mouth breathing
,there are infections in nose or nose discharge , ear infections.
Adenoids are for protection from infections in young age ,upto 7 yrs of age. But if they are enlarged and there are infections again and again that means that they are caring infection in then and which the body is unable to fight then you must get the adenoids removed by surgery- Adenoidectomy
Otherwise these adenoids have the bacteria in them which are secreting toxins which doesnt allow the child body to grow properly.
Secondly because of enlarged adenoid the oxygen
supply to body is decreased and so the growth is less and also there is mental slowness.
Thirdly due to enlarged adenoids there can be more snoring that will lead to reflux of food contents in pharynx (throat) and then complications like Sore throat
,recurrent coughing,burning sensation in throat and chest .
So consult your ENT surgeon and get her checked for tonsils also and if enlarged go for surgical removal.
Get well soon.