If you live in a northern climate, you most likely will be deficient in Vitamin D, Celiac or not. If you wear sunscreen all the time, you most likely will be deficient in Vitamin D.
It is also a fat soluable vitamin and people with Celiac can have trouble absorbing fats for life......I do. It is much improved since going gluten-free but my body still does not like high fat meals...which no one needs to eat anyway....unless you are strictly eating good fats only. As we age, the GI tract doesn't work as well as it did in our youth so all of these can combine to make obtaining good levels difficult.
Vitamin B12 absorption can be difficult in the absence of intrinsic factor in the stomach. You might want to read up on that. You may need injections for a while to get your levels up and then maintain that with vitamin supplements. Vitamin deficiencies can be tough to change in older celiacs and they can be improved but it might take some work to find the way that works for you.