@p2ionics Like, you're right, but consider, which is weirder:
-him engaged to someone physically his age
-him engaged to someone mentally his age, who is thus like more than double his physical age, which also doesn't make sense given his family wouldn't know about that, but honestly even if they did that'd be at least as weird
Of course the scenario of least resistance is him just not having a partner, especially not til everyone's at least proper adults, but an engagement isn't particularly unusual for fantasy nobles. It's not like being engaged means they have to get a certain amount close or anything. The author definitely treads a thin line with how it's all handled, I don't disagree.