3rd level subclass quests

So I've seen in a few places people positing that picking your subclass at 3rd level doesn't make any sense for Warlocks and Clerics (and to a lesser extent, Sorcerers), and I disagree.  Rather than write an essay style post, I'll just bullet point ways to roleplay that progression which would make narrative sense.

1) you're a priestess of a pantheon of gods (Norse, for example), and you don't pick which god(s) you're devoted to until 3rd level (ex. the Fates, which provides even further choice, as you get to pick between Urd, Verandi or Skuld), and if you're in Russia, the god picks you.

2) you're a kid that has a natural talent for cajoling animal/mineral/vegetable spirits to do your bidding like Snow White, which represents how you have eldritch power, until a higher Power scouts you and says "How'd you like to do really cool shit, kid?  Just sign here."

3) you think you're just an apprentice "sorcerer" to a kindly old "wizard" who told you that the power you possess is a natural talent (while he had to study to learn his) and then you realize the truth - he's been your personal battery, and if you want to keep going in your lessons a little deal needs to be made. [the Freemium model]

4) what, you never changed your major in college?

4) in the case of the genielock, you know you're going to be a genie someday, but your subclass represents your inherent elemental affinity (oh, say, based on your star chart - how many planets were in which elemental houses).  In your setting, you could be a fire-based genielock with a water genie patron.  Being a genie is being a genie - the elemental form is just drag.

5) metaphorically, you join a theatre troupe to be an assistant director and it turns out that you'd be perfect for this small but pivotal part, and you discover you have a talent for being up there. (Or vice versa, when you realize after being the lead yet again, what you really always wanted to do was direct).

6) you sign up with one outfit until another one comes along with a better offer with more benefits, and stock options.

7) your god has a lot of different domains (that don't really make any sense), and you have to choose which aspect of your god you're to emphasize.  (example: Poseidon is the god of the ocean and...horses?)

8) you don't pick which Order you belong to in the Catholic Church until you graduate.

9) frequently the powers of the Warlock are posed as a superior magical being as the source of the power, and that the Warlock is somehow beholden or subservient to that higher power.  What if it were reversed, and the Warlock was able to cajole control higher and stronger sources of magical power (they are using Charisma after all)?