It is written this way because the story is not at an end; it is going to continue. It's very similar to Sherlock Holmes stories, written by Sir Arthur Conan Doyle. The character, Dr. Watson, Holmes' friend, is telling the story as it happens, but he sometimes uses information from the past to help the reader catch up to what is happening now. Yes, I can read your question. I've lived in China.

'Have known' includes all time up to now. 'Had known' includes all time up to the moment that is defined --- in this case, the beginning of the story, not now. The word 'starts' shows the continuation of the story, perhaps bringing the story to current time. If they said 'started', the story may end at an earlier time, always being in the past, not continuing to now.

Are you looking for a teacher, or just someone to chat with? I have recently returned to US from China, where I taught university-level Oral English, and I am now accepting new, online students. If you only want to be a free language partner with other students, that’s OK. When you want some professional help, let me know.