The Life of Kishinev (dropped years ago)

This story probably has the most chessiest description. This story is about a 12 year old boy who goes to school. I know you might think that it'll be boring now that I've said that but hear me out before you leave. I'm going to make this as interesting as possible with 3 main plots. 1: he meets this girl that he kinda has feelings for but is not entirely sure. He honestly thinks that he's just no deserving of her. At one point he turns the tables by just getting sick of not being able to make a decision and starts gaining self confidence. He gets smarter, faster, stronger, and basically gets better in skill with everything overall. One day he's looks at himself and notices how far he has come and all the work he has done, has payed off. By the end of the book. He figures out that she's been noticing it and has liked him for it. So they have an adorkable moment and go out. 2: While was gaining self confidence, he works out. He learns fighting styles, mostly judo and boxing, and really become the fighter. 3: his mother has been missing for about 3 years now. And when him and his dad aren't in public and at home he's an obsessive detective. He's gets completely consumed by the case and it really has a bad effect of the relationship between the main character and the father. But by the end of the story, there's a little suprize at the end of the story.