Suggest Treatment For Large ASD In A Child

hi,my son is 5 months old n recently he has been detected with a 10mm ASD, we consulted a cardiolofist who says there is nothing to worry about n we need to wait for 2 years before anything could be done, after that if it doesnot close by itself we can go for balloon surgery, my son is 8.3 kg...what would u suggest?