My previous answer seems to be lost in cyber space, so once again my answer:
"somebody" is right. During the first months after birth often ASD's and PDA's close spontaneously.
An ASD is considered large when it is >2cm, so your son's ASD is not large and there is a good chance that it will close in the coming months.
As an ASD and PDA can put stress on the heart, it is necessary to monitor the development of the ASD and the PDA and their effects on the whole heart.
So, follow your doctors advice and consult him regularly the coming months, to see how the development is.
good luck and congratulations with the birth of your son!