One of the classic traits of YA literature is that it is written in the first person (NOTE: not all the time... But it's incredibly common). I know several people who don't read anything that isn't written in the first person because they think they won't be able to relate to it (my teenage sister-in-law included).
I've heard in some writing classes that writing in the first person is easier, that it's the lazy man's way of writing a book. To those people I say: Watch the Lizzie Bennett Diaries. I am a huge fan of this vlog (if you haven't heard of it, it's a modern-day Pride and Prejudice told from Lizzie Bennett's perspective). It seemed like everyone who watched it was crazy about it, and for good reason.
The entire story is told in front of a webcam. That means that if Mr. Darcy does something critically important, it has to happen in such a way that Lizzie talks about it or sees it happen from in front of her computer.
This is just like writing!
If something important is going to happen in the first person, then it has to be seen through the eyes of the protagonist. You can't just take a second to write a paragraph or two about the important history, or the motives of the villain. Everything will be seen through the bias of the MC- and trust me, everyone has some sort of bias. It's harder to do well than it sounds!
So if you find yourself with a huge gap of time, I highly recommend checking out The Lizzie Bennett Diaries! There's a ton that can be learned from them. But be warned: only start watching them if you have a ton of time on your hands, because you won't be able to stop!