The age of Peni Parker in the comics isn't fixed. Generally, she's shown to be in her early to mid-teens. This can change depending on the creative direction of different comic arcs.
A fanfiction could focus on Peni Parker's life outside of being a hero. It could show her struggles in school, trying to balance her studies with her duties as Spider - Man. Maybe she has a hard time making friends because she has to keep her identity a secret. This type of story would give a more human side to her character.
A great 'Miles and Peni' fanfiction usually has good chemistry between the two characters. It can be their friendship, or a more complex relationship. Also, the story should fit within the existing universe's lore. For example, it should respect the powers and backgrounds of Miles and Peni. The writing style also matters. If it's descriptive and flows well, it makes the reading experience much better. It can bring the world of Miles and Peni to life in a vivid way, making the reader feel like they are part of their adventures.
I'm not entirely sure as 'peni x miles fanfic' could refer to a fan - made fictional work about two characters named Peni and Miles. It might be a story that combines their adventures, relationships or some unique scenarios created by fans in a fictional universe.
There could be a fanfiction where Peni Parker has to deal with a personal crisis. For example, she might start to doubt her abilities as Spider - Man after a particularly difficult battle. Through this self - doubt, she has to find a way to regain her confidence and continue to protect the city.
There are many fanfics that focus on Miles and Peni in the Spider - Man world. Some might explore their friendship, like how they team up to face a new villain in their neighborhood. They could use their unique spider - powers in combination to defeat the bad guy.