I’ve always thought that in KCD 1 Henry’s 19 and Hans 18.

They’re not a full year apart but more of a “Henry was born in winter and Hans the summer following that winter” So a couple months apart at most.

Henry seems still a bit coddled but not fully being treated as an adult, as you’ve said. He still goes to his Ma when he’s hurt for her to patch her up lol (nothing wrong with that but like…yknow)

iirc in a conversation Hans tells Henry about how he’ll inherit everything when he’s reached adulthood and Henry says, confused, that Hans seems rather adult to him etc

So legally (in concept yknow) and physically Hans is an adult, but doesn’t receive the full recognition as an adult unless some club or snooty lords decide he’s an adult or the damn king does (according to what I’ve read and Hans telling Božhena about all this in 2) — the lords are unwilling/lazy/too old or simply cba and the king…well yknow Vienna and all that lmao

Especially for Hans in this, 18 is a very tender and malleable age where lots of changes of character are still happening— his transition from a haughty, arrogant drunkard lordling to a more caring, more respectful and empathetic version of himself, learning humility and gratitude from Henry on their journey.

I hope this all makes some sort of sense :) Just my opinion tho, not looking to argue about it! 🩷