Don’t be embarrassed! Sometimes these things can be confounding for a long time. I’ve been planning a sci-fi story for about six months and I still don’t know whether it’s going to be a screenplay, a first-person narrative or a third-person narrative.
What I would say about your decision is that ‘person’ is about access. If you use the first person, you’re giving your reader access to that one person’s story. If you use third person, you open it up to have different perspectives.
If your narrator’s POV is central to the reader’s understanding of the story, it’s a strong case to use first person. You’ll want to use this if:
1. Your narrator’s perspective is important to your intended meaning for the story.
2. Your narrator is able to access the majority of the storyline without missing important details.
3. Your narrator is equipped to give the reader emotional access to the important plot points of your story.
4. The story is ultimately about your narrator and how they, specifically, respond to what’s happening to them.
5. The inner thoughts of your narrator provide additional detail and experience.
6. You just like that version better.
7. You want to trick your audience. First-person narratives are unreliable because it’s not the facts as shown by an omnipresent voice, and they’re coloured by their own perception. A narrator could be lying to us at any moment, but most people trust them implicitly when they start reading.
8. Your narrator has a reason, the time and the skill to write about this story.
I think, in general, a story that places equal importance on the responses of multiple characters should be told in third person. I take that stance because I tend to dislike stories that are made up of first-person perspectives from multiple characters (bear in mind, that’s purely my own judgement; I dislike being thrown around from one mind to another), but also because I find it’s the more immersive option. You’ll need to use third person narrative if:
1. You don’t want one character’s perspective to colour the entire story.
2. You want your reader to have closer access to the psychologies of other characters without the inflection of someone else’s opinion.
3. The character who would be your narrator does not have enough access to key moments in the storyline.
4. You want/need your reader to make up their own minds without guidance.
5. You’re not able to convey what you want to say about your theme and subjects through your chosen narrator alone.
6. You just like it better that way.
7. The inner thoughts of your narrator pollute your story with unnecessary clutter/irrelevant rambling.
8. Your narrator is not the sort of character who’d write this shit down (I know it’s obvious, but I read plenty of manuscripts where the narrator claims that they’re not at all skilled with words and then they manage to create a purple-prose stuffed work of art about their own lives). You need to take into consideration the type of person you’re dealing with, the reason they’re writing, how they’d write and whether or not it’s realistic that they’d have the time to do so.
That might not help you decide too much, but if it doesn’t, just go with whichever one you like better. Some of us write more and better in third person than first, and vice versa. If you find one version more pleasurable, go with it. It’s about the pleasure.