Not necessarily. Heroes don't need to be experienced to be heroes. However they do need to make a big enough impact to be considered heroes. In other words be a part of, or actually lead a big change in a country, destiny, or fate of the world. Not all people need to be bright eyed idealists to clarify that preemptively. 
 
We will only be taking trips back to the world of the Sentinels, our characters, if, or when the player requests that a twist of fate happens there. Detail should be fair but it doesn't need hardcore the main principle should be fleshing out the hero in question, and their impact on the world.