Praise be to Allah.
Adam (peace be upon him) was the first of the Prophets, as it says in the hadeeth narrated by Ibn Hibbaan in his Saheeh, that the Prophet (peace and blessings of Allaah be upon him) was asked about Adam – was he a Prophet? He said, “Yes, a Prophet to whom Allaah spoke.” But he was not a Messenger, because of the hadeeth about intercession in which it says that the people will go to Nooh and say to him, “You are the first Messenger whom Allaah sent to the earth.”
This text clearly indicates that Nooh was the first of the Messengers. And Allaah knows best.
Majmoo’ Fataawa Ibn ‘Uthaymeen, 1/317.
Adam the father of mankind was a Prophet, so he was the first of the Prophets.