If you start the game as a kid, there could be a quest line related to each potential CM, and at the completion of it...it's a bit like a Pokemon evolving...you get a little cue saying 'hey, what's that on your side?'
If you accept the mark, you the mark of the quest in your own choice...if you decline, the cue goes Opp, never mind, it's nothing.
But...that potential mark is now always there, and you can change your mind if you want by selecting it...but once you've chosen it...that's it.
This would encourage players to 'shop around for a mark'.
And some quest ideas:
The cooking quest starts with you learning to cook, and ends with you making dinner for an important visiting relative.
The sports quest starts with you getting brought into a team to cover for an injury, and ends with you playing in the final.
The fighting quest starts with you defending a kid, and ends with you taking on the bully.