What do you think of this plot?

Seems like you plan for it to be a feel good story about redemption and finding yourself for the young girl. Straight from what you've said there though, you would need to answer clearly how that note got to the girl, because otherwise that's a gaping plot hole right there. Honestly, I like books that do the time jumps. They can be confusing though, and usually require two separate voices or tones, along with knowledge of the settings in both aspects. So it would require research.