Diamond Tiara presents a mean, manipulative exterior to her fellow ponies at times - and it turns out she knows it. She doesn't claim to have a cute and snuggly inner self, but she does have concerns. About herself, about destiny, about her cutie mark.

In a bout of insecurity, she writes an entry into a diary she was given at the party celebrating her cutie mark, venting her fears and confusion to an inanimate object incapable of judging her or telling her that she needs to be more harmonious. Who is she, really? What is she meant to be? If she knew, perhaps she'd feel better, but she doesn't.

This story could be taken as a side story to some of my other works, but it could also stand on its own.

It isn't very often that a scholar has the opportunity to discuss knowledge from other worlds with someone who actually came from one, but Twilight is one of the lucky ones. A being called a Pokemon, identifying himself as something termed 'Mewtwo' has ended up in Equestria, and Twilight is bound and determined to learn whatever she can from him - even if it means asking embarrassing questions. After all, what sense do Egg Groups even make?

Aside from gaining new information, Twilight also hopes to form a bond of friendship with the intellectual Mewtwo - named Grimalkin - based on their shared scholarly nature. Their discussions range from the history of both of their worlds, to matters of physiology - this particular talk being focused on the curious matter of Pokemon reproduction.

This fiction may yet tie in with other stories of mine as a side story, but it could potentially stand on its own.
As reproduction is only alluded to, rather than described in great detail, I believe this rates as Teen.