Is 11 Years Old Too Young for Septoplasty Surgery?

My son is almost 11 years old and he has total nasal obstruction. He also has severe allergies from dust and pollen and his nose is constantly blocked causing breathing problems. He has to always breathe from his mouth. His ENT suggests a Septoplasty surgery. I'm concerned that he's too young and he's nose structure is still growing. The ENT says that by not doing a surgery now, he's facial maxillary will not develop properly. Is 11 years too young for this surgery?