Dear S. B. …
That declaration is too intransigent for me. First-person POV is perfect for some projects, and in some markets—like Young Adult fiction—it’s even the dominant choice. Gauge your target market’s expectations by reviewing its current big books. Looking at the story itself, I suspect that “comfort” you’re feeling is your gut saying, “Good choice for your info delivery needs.” First person has a sort of tunnel vision that limits readers to knowing and observing only what the narrator is privy too. You’d feel it if you were battling that limitation while trying to get readers the info they need. In that case, beta readers would complain about awkward or unnatural scenes and dialogue. That’s when I’d raise my editorial flag and say, “Try third.” I suspect you’re also comfortable with the narrating character’s voice—which is huge. If you can’t truly feel like—can’t be—that character while you’re writing, then get out of her head and try third person, which distances you from the character a bit so you can create a narrative voice that’s less her and more you.