I'm fully prepared for this to be crushed in-game but...
Notice, if you will, that it doesn't mention you being the youngest in the mage description. If they don't specify you as the youngest if you're a mage, I'm going to headcanon that there are two potential human protagonists and they're both from the same family. It provides good flavor for the backstory for me, if nothing else.
This here. It was already my headcanon, long before we got the character blurbs, that my female human rogue and male human mage would be siblings, both would be present at the starting event, and each of their playthroughs would be the "what if" of the fallout - brother dies in explosion, sister becomes Inquisitor; sister dies in explosion, brother becomes Inquisitor. Now that we have the official backstories, I'm just beyond myself with how perfectly the whole thing fits that headcanon. The siblings attend the event together in the same group representing Ostwick, he as a Circle mage and she as a Chantry scholar, things go boom, and whoever survives in one alternate reality or the other goes on to lead the Inquisition, carrying the memory of their lost sibling. Just as planned.