Anas ibn Malik reported:
The Messenger of Allah, peace and blessings be upon him, would pass by young boys and greet them with peace.
Allah Almighty says:
'And you are of a great moral character.' (Surah al-Qalam, 4)
The Messenger of Allah peace be upon him did not say: 'This is a young boy. Shall I salute this?' But he would greet everyone. We must follow this sunnah and spread the greeting of adults and children widely.
May Allah help us all to follow the sunnah of our beloved Prophet and become one of his beloved ummah in this world, and in the Hereafter, we will have his intercession!