Sounds perfectly reasonable to me. You might want to specify that the soda be cold. Saves on "starving" teenage time.
The kiddos I camp with (ages 9-14)make their own breakfast 3 days outta 7; are required to make an appearance at lunch and dinner time with clean hands, set the table and wash the dishes(I checked my contract. Dishwashing isn't listed and the maid is NEVER anywhere to be found despite being taken on vac with us every year. Whadda lazy hussy!).
I set up a specific snack area in the camp kitchen where they can scoff stuff with wild abandon. Saves me from planned dinners/lunches being snuffed out.
Have fun!