First person means you write the story from the “I” viewpoint. When constructed well, this brings about a personal connection with the narrator. Many detective and private-eye novels thrust the narrator into the middle of the action. Readers can identify with and become the "I" who solves the problem.
Gothic novels are no longer popular, but they focused on the first person's perception. (Gothics began with Jane Eyre and include Rebecca as the most outstanding modern version. The "I" narrator is an insecure, sensitive heroine in a castle or mansion, often isolated, and her life is frequently threatened.)
The power of first-person accounts is that they foreshadow events, often evil or catastrophe, and do them through the foreboding or troubled heart of the protagonist.
In the older gothics, they often used the If-only-I-had-known technique to create suspense. Readers experienced doubt, fear, and insecurity along with the narrator. Because readers are the narrator, they learn only when the narrator does and can create suspense.
First-person POV works for specific reasons.
Before you try it, be sure it works for you.