I did that till he was pretty much 3 on the dot for most things. Sometimes I will still cut up a hotdog (ds is almost 5). :) I have friends that feed their 18mo baby carrots. Makes me crazy!
I really didn't worry about pb as a choking hazard though. Some is less sticky, imo. I think of Jif as really sticky and mouth filling but I don't have the same experience with the fresh made pb at the natural food store or Whole Foods.
Beth