Storytime Favorites discussion

I work for the Public Library in my city. I'm prepping for a Storytime at a preschool in May. The teacher likes my visits to be theme based, and this month she's asked for a "look at how you've grown" theme. She explains it as "Kind of a wrap up theme we do talking about summer, going to kindergarten, friends we've made, things we've learned etc".

Any suggestions for some great Storytime books? Most of these children are 4 years old.

Thanks in advance!