What happens to the discernment process if you made some big mistakes in your life? Does that mean that you are no longer a good candidate for seminary? If you confess your sins, repent and ask for forgiveness, you will be forgiven.
The sacrament of Holy Orders, though it gives in abundance God’s grace to live up to the demands of the call, does not guarantee or even grant perfection in this life. Priests are still human, and are fallible, sinful men. However, if you make Jesus the overall motivating force in your life, then you will continue to grow in virtue. To mature spiritually, all of us must be dedicated to daily prayer, to obtaining a deeper knowledge of Jesus Christ through prayer and study, and to make use of the frequent reception of the sacraments, especially the Holy Eucharist and Confession. A man who follows this path will not mess up big. If we truly love the Lord and desire to do His will, He will provide all the grace we need to live up to our vows as a priest. It is when we lose sight of the face of Christ, when we stop our daily prayerful communication with Him, and when we do not make use of the sacraments, then we are setting ourselves up for a great fall, no matter what our vocation is.