As a writer, it's pretty simple to say that you don't know everything at once. You learn as you go, and, in fact, may not know the term of something you are writing, though you know that something is off when certain rules are broken.
Such was the case with first person, second person and third person.
Because POV (point of view) runs a close race with the above perspectives it was easy for me to get everything convoluted and a bit mixed up when it came to knowing what a writer was actually writing. So here it is as simple and as straightforward as I can make it:
First person: I
Second person: You
Third person: He, She
External Narrator: The narrator stands outside the story as the story is being told
Internal Narrator: The character or characters are telling the story
Things get confusing as you try to figure out what the narrator's orientation is. For example, what is the distance of the narrator, very close or very far away? First person tends to bring readers closer to the story, while third person keeps the readers more at a distance. But by reining in the reader through an internal narrator, your reader feels as if he/she has moved closer to the story.
Problems arise when the writer shifts gears within the paragraph, even within the chapter. If a story is told from a third person internal narrator, for example, the story must run true throughout. You wouldn't want to suddenly shift to an external narrator, for example.
Here is a simple but effective chart putting the two issues together.
It's always great to learn new things, even technical things because knowing them will not only help your writing to improve but perhaps even the writing of a fellow writer as was the case with me.