When i was 12 years old, i knew i was called to preach. i walked up to the preacher and asked him, what must i do to become a preacher. What he told me, i was not expecting. He said "You must go to college for four years" i immediately said, that is pretty sad if God calls upon a poor person to preach" and walked away.
There are a few who are actually called to be preachers.
There are many who choose to become preachers because it appeals to them.
i was called to be a preacher before i was even born. my Mom was going to be a Nun, then she met my Dad, and fell in Love with him, they married and had me, my Mom felt so guilty about turning away from her calling to be a Nun, that she prayed to God there her firstborn son would be dedicated to the Lord. So when i was in the womb of my Mother, she only read the Bible to me. i can't remember a time in my life that i did not know and believe in Jesus. i believed in Jesus before i even believed in Santa Clause.
my point is. God calls whom He will call. and God will educate a person in what they need to preach. Is it not the Holy Ghost that reveals Truths to a person? No not this generation Truth is revealed to a person through college now, through professors, through books and essays.
Your preacher felt you are far too young to preach, because you have not yet been to college for four years.
i will tell you the Truth the Holy Spirit of Truth can teach a person in five minutes what it will take a year in college to grasp and understand. The problem is the people that belong to the Churches, choose a preacher, and they base their choosing, if they had been to college or not.
As i said before, Few are actually called to preach, Many go to college to become preachers because being a preacher appeals to them.
Those who Truly desire to be Preachers of God, will seek the guidance of the Holy Ghost, not the guidance of professors.
Responding to OP