I don't think they had chipmunks when i was a kid, but i still have my first firearm. It is a .22 bolt single shot. I will never forget that Christmas morning. I opened that present first and quit looking for others. My dad took me outside, explained how to work the rifle and how the sights were similar to my BB gun, and gave me a .22 short hollow point. I capped a squirrel. I don't remember any other Christmas moment as clearly as that, and it has been about 32 years.
Chipmunk, for sure, and get a pic of your kid's face when the paper comes off the rifle.