One of the inherent troubles with a retrospective novel is that readers know the narrator is telling the story from a point in the future. The events have happened, and the narrator survived them (since they're telling the story). So there's very little fear about the narrator surviving. To combat this, you'll often see a narrator who's at a point where they're about to die, and they're telling their story before they're gone. Again, this has tension issues because you know they made it to this point, and if they're about to die, why does any of it matter? Writing retrospective that works well takes skill.
And John Marsden has that skill.
Tomorrow, When the War Began by John Marsden
This was a great book and one I really enjoyed. Australian teens come back from a camping trip to find their country's been invaded, and they decide to live off the land and fight back guerrilla style and save their families. There are seven (I think) in the series, and I'm going to have to order them soon.
The book is told in first person retrospective. The narrator, Ellie, is given the task to write down what's going on so there's a record of what this group of teens did/are doing/have done in case of disaster. She keeps the journal of their experiences so folks will know they existed and acted.
Retrospective is something you don't see a lot of in YA, because looking back on events is usually done from a later point in life. But Marsden brilliantly used the war to provide that "looking back" feel, because the teens have newer, "older" perspectives on life now that war has been dumped on them. It's an interesting -- and effective -- way to handle it. Ellie can see the difference between now and when she was "innocent" and can long for those days again, even though she knows things will never be the same. She's still a teen with teen perspectives, they're just changing. (showing character growth as well, so you get a double does of storytelling goodness)
But Tomorrow never loses the feel of a YA novel. It's fast-paced, has teens making tough choices and mistakes despite their growing wisdom. The narrative catches up to the present and it turns into a journal written after the fact, so it maintains that retrospective feel. Yet it's about events happening "right now" so you never lose the tension of wondering what might happen next. Ellie is in serious danger, so retrospective or not, she might not live to write the next day's entry.
Marsden also doesn't overuse the "little did I know then" device and having the narrator chime in with personal thoughts to tease the reader. Ellie makes comments from the "present day" perspective, but it's usually about something poignant she's figured out, not a tease. It's also slowly turning into her journal and how she's dealing with things as much as a record of what's happening. A very nice way to show her growth, suck you into her character, and get you to really care about these teens.
If you have a retrospective story idea -- YA or not -- I highly recommend picking up this book (and series) and seeing how Marsden did it.