My DW is celiac and has to be very careful. We always pre inform whichever cruise line we will be sailing with. NCL has a profile on their webpage that allows you to list such things. However, just to be certain we have it included on our reservation. We also contact the maître d' in the MDR at the start of each cruise. DW has had the best choices by preordering meals for the following days. This can be done in any of the restaurants, except maybe for the buffet.
This being said, we had two unfortunate instances in the MDR on our most recent Alaska sailing in June on the SUN. On two different days during dinner, DW was served what appeared to be gluten food items. Each time the waiter insisted that the meal was prepared gluten free just as it had been preordered. I insisted on speaking with the maitre d' and the chef to confirm if the waiter was correct. In both cases the chef came to the dining room and agreed that her meal did indeed contain gluten. The chef stated that the waiter had either taken the wrong prepared meal, or the plates were switched after being moved to the waiters serving station in the MDR. This could have resulted in a serious illness and a ruined vacation. When we reviewed our cruise with NCL, we strongly recommended better training for their wait staff.
To the OP, I wish you success, but warn you to also be vigilant. Many ships seem to be dealing with lower staffing levels and less experienced staff.