Adenoid hypertrophy. 5 years?

My 3.5 year old daughter breaths through mouth for more than 2 years. While we consulted ENT doctor he has told that the air veins are blocked and asked to give cepodem, delcan, aerodil syrups & nebulisation for 5 days. After these medication, she is freely breathing but still through mouth. After that he checked & told some noise he is hearing & asked us to get nose X ray and it is showing as adenoid hypertrophy. After checking X ray film, he told that, she is suffering from Grade 4 adenoid hypertrophy & advising to go for "Endoscopic debrider adenoidectomy". Requesting to provide your opinions on above whether we need to go for it or not and will there be any side effects. Can it be cured by only medication? Is it advisable at age of 3.5 years?