My 3 year old daughter was diagnosed 6 weeks ago. She is very snacky too, so we were very concerned about how we were going to get her adjusted. Definitely the cheese, peanut butter, bacon, nuts were great options, but sometimes she craves snacks that are more “carby,” if you know what I mean. So our favorite right now is popcorn! A cup of popcorn is 5 g of carbs or less (check the package, of course). And there are lots of flavors. For example, we just found one that’s bacon ranch flavored and is delicious! I’m sure a cup of popcorn is not enough to satisfy a growing 14 year old, however you could consider adding a beef stick or string cheese along with it.
Best of luck!