Personally I don't have a problem with the age gap the reasons being because, one trying to apply modern standards to a world of manga is weird in itself. Two in the past of the real world girls were married between ages 12-18, if you were past 18 you were considered an old maid and unmarriageable. And three even in modern times you can still get married at 15-16 years old with permission from the parents (knew someone who got married with her parents permission) or if you are emancipated and are considered an adult. Also I have heard of 18y.o. marrying a 90y.o. in modern times so I try not to judge to much. What I have a major problem with is when they are forced to do so and have no say in their life. The former king and Rodan gave her the choice, as it would be the best way to protect her, as she is considered marriageable in that world. If she was kidnapped and forced to marry maybe in their world they can force a contract on someone without consent that they can't do anything about (just guessing don't know for sure). The former King and his group won't do it because they have a conscious but doesn't mean other's won't. Current Nylle family an example.
Trying to find a, I think, webtoon the girl's mom was strangled in front of her by a maid and I think she is the prime minister's daughter and she somehow goes back in time but after her mother has already died. Well anyways since I forgot to bookmark it I would appreciate it if anyone could help!! Thank you!!
Missing chapters 59-61