A character doesn't need the mindset of an adult at birth to grow up hating their parents/family and distrust all adults. The abuse and neglect is enough to do so. If they really did think like adults, they would know not to trust any adult just because they show kindness. The plot point of them having memories of their previous life is pointless, honestly. They are still mentally at the level of a child. Since they grew up a bit, I'd say around a 7-10 year old which is nothing near the level of 18+. There is too much continuous flip-flopping between trust and distrust between the twins and their family. I don't get why they aren't suspicious of the Count. So they are choose to distrust their royal family who've offered protections thus far, but don't even think twice about be offered a servant from some random nobleman when people just tried to murder them. Yup. Alright. Adult-minded. If surviving was their goal, why do they turn brainless when the convenient villain Count Rose plot points happen?
I did enjoy reading this up to a certain point, but the lack of development in the twins is somewhat aggravating. The twins and the royal family. Lack of communication is the most irritating plot tool.