Point of view is not the same thing as narrative form. Just because your character is the hero or heroine does not mean you have to write in their voice. Though it is always tempting to write in first person, placing yourself, the writer, as the hero or heroine. (Question: if a guy writes the heroine in first person, what does that say about the guy's feminine side?).
Not all narratives that are first person use the word, 'I'. When you read a blog, you know whose opinion is being touted. But when you tell a story the narrator may or may not be the character in the story. In the Sherlock Holmes stories, the narrator is Dr. Watson. So he 'tells' the story from his own point of view, but not always in the first person. The third person is the reader. So third person narrative involves letting the reader know things even if some or all of the characters don't know. This is not nearly as hard as it might sound. If you're writing about characters who lived during World War II, for instance, you, and the reader (generally) know about events that the characters have not yet experienced. This creates a dramatic irony and suspense that you can present to the reader through revelation to the character who may be narrating their surprise or disbelief in facts that the reader already knows (and if they don't it's a good way for them to learn).
I've noticed a trend in writing today that uses first person to narrate the main character's point of view and third person to narrate everyone else's point of view. This can be used to limit what the reader knows to the mind of the hero and the camera view which limits the reader to what the hero might see (if they are in the scene). I am trying that with Deliberate Acts - might use it, might not. I'll wait on a decision until I have both variations in a couple of chapters.