The protagonist is usually the first character you create for a story as well as the most developed. They are important because the reader needs to stick with them until the story ends and they are often the readers main guide through your setting no matter if you have set your story in a magical kingdom, sleepy modern town, or a bustling space city. Because of this you need to make sure that your protagonist is at least moderately interesting so that your reader won’t get bored, or at least introduce some other more interesting characters and/or settings.
Your protagonist can be anyone. The only rule is that they shouldn’t think that they are the protagonist of the story unless you want your character to be Narcissus. In real life very few people think of themselves as protagonists. They think of themselves as minor characters in the overarching story. To make this more obvious create a character for the sole purpose of appearing as a protagonist to the actual protagonist.