The game I am working on is a class-less at the moment, instead focusing on players being able to simply choose a variety of Abilities to craft their character at generation. I am, however, considering a functionality that allows for characters to go through their early life (as adventurers) learning about the things that most interest them until they choose a path in life, or a Calling. This would be their "class", though it only grants them a few new features. I am trying to make these features powerful to justify their late acquisition but also don't want them to be crucial.

I am mostly looking for:

A) Suggestions on games that do something similar; and

B) Critique on a system like this.

I'm also curious as to whether having an alternative wherein some character may decide to choose not to take such a path and what the costs/drawbacks for those players who do might be. For example, if two players in a 5-player party decide to follow their calling, do they get a penalty or do the other players who don't choose to do so get a benefit?