I have a headcanon that lives in my head as the “Weasley headcanon” that comes from the fact that Diluc is said to be the youngest captain of the Knights at age 14, but Jean is said, without as much fanfare, to have been named Dandelion Knight at age 15.
Every time I try to check the chronology of some events and the hierarchy among the Knights, I realize again and again that a lot of things aren’t actually strictly specified… but the way I see it, I think Dandelion Knight is not just any title and might very well mean that Jean got appointed as Varka’s second in command that day, which could be the rank mentioned as “Master of the Knights”. And we know she was a captain before being Master of the Knights, so it would mean that Jean was probably also a captain when she was 14. But nobody talks about it.
Also, I think Jean is 2 to 3 years younger than Diluc. The Eroch ordeal happened around the time when Jean was promoted to Master of the Knights (I’m realzing… again… that it is not as clearly stated as I thought), so it means that Jean was around 15 or 16 when Diluc was 18.
So my headcanon is that Jean was actually as successful as Diluc and her history in the Knights was as impressive as his, with her rising through the ranks as early as he did, but it never really left a mark because Jean is younger so she did everything after Diluc.
Both Jean and Diluc come from prestigious families, so there are a lot of expectations on their shoulders, coming both from the people of Mondstadt and their parents. I think Frederica, as involved as she is with Jean’s education, might very well see the Ragnvindr heir being such a golden child, getting his Vision at 10, being accepted in the Knights early, getting promoted as Cavalry Captain at 14, and become anxious that the Gunnhildr heir could be less impressive than him… And then Jean turns 10, and she doesn’t have a Vision, and she’s good but still, Diluc already had a Vision by that time and Jean doesn’t… I also headcanon a few old family tensions and rivalries to add spice, so Jean’s mom would really like if her daughter could be as good as the Ragnvindr son…
Everyone is impressed by Diluc and he becomes known to be the youngest captain in the Knights’ history. And then Jean becomes a captain too, at the same age, but… nobody really notices, because Diluc already did this impressive thing two years prior. Jean is a young captain… but by the time Jean becomes a young captain, Diluc is already an experienced young captain with probably a few known deeds attached to his name. It’s not that Jean is not as good as him, it’s just that Jean is not as good as him yet. Because she is two years younger. She is always behind him, because she is always younger and less experienced than him. At a given time, Diluc is always ahead of her, but if you compare what Diluc and Jean have accomplished at the same point of their life, it’s pretty much the same. But most of the time, nobody stops and think fourteen year old Jean Gunnhildr is as good as fourteen year old Diluc Ragnvindr. They just think the Gunnhildr heir was made captain two years after the Ragnvindr heir.
As Ron Weasley would say: “everyone expects me to do as well as the others, but if I do, it’s no big deal, because they did it first.”
Except that Jean sees it more like “he did it first because he’s better” and who is gonna correct her? Frederica Gunnhildr?? No I don’t think so.
To add insult to the injury, I think people tend to be more impressed by Diluc because he is more eloquent. In his own way. I mean Jean is definitely more eloquent than him, but Jean is mostly more diplomatic while Diluc is more passionate in his way to express himself and diplomacy tends to be less impressive than passion. Jean is polite and speaks in a measured way and will conceal her own feelings if it benefits Mondstadt, while Diluc will speak his mind with as much animosity as he pleases at any given time. Even in battle, Diluc will scream “BUURN” while sending a freaking fire phoenix on the battlefield, while Jean will settle for a calm and pious “wind, hear me” and focus more on healing her allies than unleashing her rage on her enemies. Diluc is bolder and boldness can get mixed up with strength.
Also he is the heir of the richest family in Mondstadt and number one producer of wine (and wine is important!!!), he isn’t known solely as a knight. He is interesting to the public for other reasons, while Jean’s family background is more focused on the knights only. I think the Gunnhildr family present themselves more as ready to sacrifice all they have in order to devote themselves to serve Mondstadt while the Ragnvindr family… is known to be the wealthiest family… We don’t know if the traditional vow of poverty is a thing in Mondstadt, but it might since there was a history of rebellion against the aristocracy, and I do imagine that if it is a thing, the Gunnhildr family probably abides by it, while the Ragnvindr family clearly doesn’t.
Jean is a lot more modest and discreet in a lot of aspects.
I think things ended up evening out when they reached adulthood and a two year gap became less significant. 20 year old Jean is not behind 22 year old Diluc anymore. But it did leave its mark on Jean’s self esteem and now she is the Acting Grand Master, the second highest rank among the Knights, and presently the highest as long as Varka is away, but she still refers to Diluc as her superior (let’s not mention the fact that he isn’t even a knight anymore). What do you want, it’s a race she’s been losing for twenty years, it’s hard to realize that she was never even behind in the first place.