God can call any man he chooses to become a priest, any time he chooses, and under any circumstances he chooses. You have only to join a gathering of priests anywhere, or visit a seminary, to realise that there is no such thing as one single ‘priestly type’ that God calls to be a priest. Priests are people as varied as any other group, widely different in interests, temperament and background. Sometimes you may even be surprised by whom God calls, especially if He is calling you.
One of the first things that you may think of if God is calling you to priesthood, is that you are not worthy. You are not alone, no one who is called is worthy. You may question God, “You know that I am a sinner, you know my weakness, there are much holier men than me why don’t you call them?” God in his divine wisdom calls those whom he wants to call. If you have the feeling that God is calling you to the priesthood, remember that He will prepare you for the work of a priest by His grace; nothing is impossible to God. The only way to know if God is calling you to the priesthood is to begin to discern His call.