Isn't he a little young to start that?

Friday night, Scott and I went to the temple for a sealing assignment. We had a great evening in the temple, and even stopped for ice cream at the DQ with some friends. We got home around 10:30 only to find Adam still wide awake with the babysitter. Now, this is our favorite babysitter, and Adam absolutely loves her. Every time she's watched Adam, we come home to a cleaned up house and a boy fast asleep in his bed - so we were a little surprised! Apparently, after eating a few chicken nuggets for dinner, he started complaining. "My tummy feels sick", and he said it over and over until the babysitter was convinced that Adam was sick. When she suggested it was time for him to go to bed, he said he couldn't because "my tummy feels sick". He convinced her he needed to stay up until mommy and daddy got home, because "my tummy feels sick". As soon as I walked in the door and the sitter was telling me what was going on, Adam walked up and said "my tummy feels better now". I think our 16 year old babysitter got played by a 3 year old....
I wonder what we have to look forward too as he gets older... should I be scared?