You reviewed my one-shot, so now I review your story. Actually, you reviewed all of mine which was pretty nice.
Anyway, I do love this so far. Interesting beginning for a fanfic like this. I like how the Pikachu's nickname isn't something really cliche, like Sparky or Zap. I also love how you don't go overboard with the Pokemon talking like most stories do. Every other paragraph is Pikachu speaking unknown words and it gets annoying. Yours doesn't do that. Yay.
Grammar and spelling were great; just a few problems with it.
You were doing so good with this until the middle of the chapter!
“I’m glad I don’t look like a total dork.” she chuckled, inspecting herself on her hung mirror.
You need a comma after dork (lol), and that goes for all the other times you put a period instead of a comma.
Also, this is just me.. probably.. but I don't think the apostrophes around Sen's thoughts are necessary. If they're just in italics, then that should definitely be enough for the reader to know Sen is thinking something.
One last thing:
Type out your numbers. When it is below one-hundred, then I don't see why you can't type it out. o= Yes, I am talking about Sen at the store.
Anyway, I haven't read all of chapter two yet, but I'm looking forward to it, and more.