What signs are there that Auggie is growing up when he prepares to get ready for camp?

From the text:

I asked Mom to buy me a new rolling duffel bag because my old one had Star Wars stuff on it, and there was no way I was going to take that to the fifth-grade nature retreat.

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"I can bring Baboo," I said. That was my favorite stuffed animal when I was little. A small black bear with a soft black nose.
"You don't really sleep with him anymore, do you?" said Mom.
"No, but I keep him in my closet in case I wake up in the middle of the night and can't get back to sleep," I said. "I could hide him in my bag. No one would know."