First Person? Third Person? Which shall I choose? Make the wrong decision and I might have to write the whole manuscript over. Heaven forbid!
Who is the best narrator for your story?
To choose the best narrator, you must decide who is in the best position to learn the most during the story. Who has the most to gain/lose in the plot? This character might be the best choice for the narrator.
In Twilight, Bella tells the story in first person narration. It gives us an intimate look at what she thinks or feels about Edward, his family, and the Vampire World. How would the story have been different if Edward, Jacob, or Charlie would have been the narrator. Very different, I think.
One of the advantages of Third Person is that the opportunity is there for the writer to explore multiple perspectives. For example, The Mortal Instruments series has multiple perspectives based on scene. Cassandra Clare doesn't switch perspectives within a scene, but she does from one scene to another. One scene could be from Clary's POV and another might be from Simon's POV.
I think the main point to consider is not pairing narrator and protagonist, but pair narrator with theme. Who is the most changed? Who learns the lesson?
A lot of YA novels are written in First Person because the audience likes that intimate feel from one character. The choice, though, is yours.