Tennis Supremacy: Double Star Time Travel: the Rise of the Demon Coach

At the beginning of the first chapter, the brother and sister were only 10-year-old orphans (they couldn't even leave the orphanage and had no ability to study in depth), but in the second chapter, they turned into "adult thinking in previous lives"? ? ? ? ? ? Moreover, the female protagonist's data analysis and the male protagonist's ability to understand data analysis are all described according to adult standards, which is completely inconsistent with the background setting at the beginning. If the protagonist was really that powerful and mature, he wouldn't have been bullied so badly in the orphanage in the first chapter and couldn't take revenge and go back. Moreover, after the twins traveled through time in Chapter 1, it can be known that they do not have the memories of the original owners. Even if a pair of smart and gifted geniuses cannot receive adequate education (the orphanage certainly does not have the conditions to provide them with any help, they can only study with those normal ordinary children. If they want to learn more deeply and have access to textbooks for grade 4 and above in elementary school, there is probably no way), they will not have the memories of the original owners. Memory (the memory of the original owner, except for those moments with family and servants, is the memory of education, the most precious to the protagonist is the memory of education, because the original owner is a 15-year-old boy from a chaebol family who received elite education). Even if there is a system, it is impossible for a person with an education level of only the third grade of elementary school to understand those materials. Only an adult genius with at least 18 years of education can understand...