The process of discovering God’s will for your life is called “discernment”. Since our true vocation has to be discovered with the help of the Holy Spirit it is important for all men and women to give time and effort to discerning their vocation.
Discernment can be difficult because we often have our own idea of what we would like to do with our lives but God’s plans do not necessarily coincide with our own. For example, most young men hope one day to marry and settle down with a family. It can be quite a shock to discover that God may be asking something more of them. God’s plans are not ours and we should not forget that in the Gospels Jesus gets into Peter’s boat without asking permission and in so doing he changes the direction of his life completely.
Don’t be surprised to find the discernment process challenging, especially if it becomes clear that the Lord is calling you to a path you had not expected. When the Angel Gabriel spoke to Our Lady we are told she was “greatly disturbed” at his words. The attitudes of surprise or inner turmoil are not themselves signs that you do not have a vocation. In fact the opposite is probably true.
Although it begins in your heart discernment is always a two-way process. You cannot know your vocation with certainty, it has to be confirmed by the Church. So while discernment begins in the heart of the individual, it is also carried out by the Church which is why, at a very simple level, you should take it seriously when someone tells you they think you would make a good priest. Ultimately it is the Church, in the person of the bishop, who decides whether a man is called to priesthood. A practical consequence of this is that we shouldn’t delay contacting the Vocations Director. We can never be certain by ourselves. We have to allow the Church to discern as well.