I was baptized at 9 years of age. I was then a "Minister".
JW Ministers are any JWs that are baptized. Even irregular or inactive JWs are still "Ministers".
Most JW Ministers actually meet very few people and convert them to the religion. Even when many do meet a "householder" and leave literature, it is not uncommon to rarely ever see the person you are trying to convert again. BUT, the fact that they got witnessed to by you now puts the ball in their own court. They could never say they were not given the opportunity to enter into the "Ark of Salvation, Jehovah's Organization".
Being a Jehovah's Witness Minister is clearly a heavy responsibility!