Harry/Hermione
Yes. She probably could have handled it better, spoken to you first. She worries about what you think, clearly. Which doesn't justify it- it just says you mean a lot to her.
You don't have to approve, but trying to ..talk her through this or tell her she's doing the wrong thing? Unfortunately if it turns out to be a mistake, it's her's to make. Anything you say against this.. man, is just going to push her away.
I imagine it does make it more difficult. But ..at least you've some sort of relationship with her already?