I've just known that you already made the second part. Pretty good! But I found little misspellings xD
It should be 'Sonoko-neechan'. Or, you did it on purpose? If that so, then it's okay ^^
As for the whole story...
Even I'm a ConAi, but I feel little bit uncomfortable with the story. You made them all out of characters, but since it's a fanfiction then it's okay anyways, you could wrote whatever you thought of xD Also, when Conan and Ai already called each other with their names, it sounded bit weird for me. So far, it's nice. You have to keep it up, but you also have to remember their original personalities. Looking forward to the next update! xD