Through college and, serving as a youth minister for a while afterward, I always wanted to learn to play the guitar. But I never had the money to buy one so it would have been a little hard for me to take lessons. Well, one summer, my father-in-law, who was pastor at the church where I was doing music and youth went on a mission trip to Myanmar. He came back with a hand-crafted guitar that he had bought in a market for $35. My father-in-law handed me the guitar, gave me a book about how to play it and said the rest was up to me. Two weeks later, he told me that he wanted to have worship in the Fellowship Hall and that he wanted me to lead worship with my guitar. Two weeks later.
I didn't play guitar anywhere near as well as I would have liked and only knew a fraction of the chords and strum patterns that I know now. So, I picked songs that I could play with what I knew and did what I could. I've been leading worship with a guitar ever since, learning more and more about how to actually play as I go.
In Acts 18, Apollos' story resembles my experience with the guitar. Apollos was in Corinth teaching and preaching about Jesus when two of Paul's friends, Priscilla and Aquila encountered him. Scripture records that Apollos "spoke and taught about Jesus accurately, although he knew only John's baptism." (Acts 18:25, HCSB) Priscilla and Aquila filled in the gaps for Apollos and then he kept right on preaching about Jesus, doing exactly what he was doing before but being more informed than he had been.
When it comes to sharing the Gospel with people, sometimes we think that we have to have all the answers to all the questions, that we have to understand everything perfectly or, at least, a lot better than we do right now before we can tell people about Jesus. Apollos shows us that is not the case. Notice what Acts 18:25 said about Apollos, "he taught about Jesus accurately" even though there was a lot he didn't know. To share the Gospel, you don't have to know everything, you just have to be willing to share what you do know. Tell people why you believe, tell them what Jesus has done in your life, and if they ask a question that you can't answer, it is okay to say, "I don't know."
You may not be a Bible scholar, but you know enough that you made a decision for Christ. Don't ever let what you don't know overshadow what you do know.