What can I write inside the baby keepsake box I'm making?

Okay so I'm making a baby keep sake box for my niece who will be born in around 4/5 weeks :D (cant wait) Anyways, I want to write something nice like a paragraph on the inside of the lid to make it a bit more personalized but have no clue what to write. I was thinking starting it something along the lines of "To mummy, daddy and baby *her name*, May you fill this box with all your memories....etc etc" Thats when I get stuck. If anyone has any better ideas on what I can write please answer :) I'm really bad at things like this so need all the help I can get! Thank you in advance