I understand it that we are all called TO MINISTER (which means "to serve", not necessarily CALLED to MINISTRY (the PUBLIC/PULPIT type of activities). We are called to serve one another in the giftings, inclinations that the Lord has given. For example, my mom ain't trying to speak in front of folk, but she feels (and does) have what she humbly describes as a "greeting card" ministry in that if/when the Lord impresses somebody on her heart, she will feel led to send them some kind of card of encouragement. So it could be said she has a gift of exhortation (Romans 12:8) which she expresses through greeting cards.
I kinda knew early on in life that the Lord put something on me to be an intercessor. Even as a child/teen, when I prayed, things happened. I can feel burdens at times and I would run from them until I learned what to do with those burdens: to PRAY.
When I came into my present church home and began to learn more about ministry giftings and callings and specific functions that exist in the body of Christ, such things became clearer. I have been told I have a teaching gift; I am being challenged in this area, even though for my career I am working toward being a university professor...sometimes I wonder if I have the goods.
On the spiritual/ministry side, I believe I'm sensing that teaching gift more strongly because of my deep, sincere, firesome passion for TRUTH, and that's what the role of the teacher is in the Body of Christ: to proclaim and explain biblical truths to water and refresh the people.