I have coeliac disease, but I was diagnosed at the age of 23. In some ways it was harder being diagnosed as an adult because I have vivid memories of some of the foods I loved.
It can seem a lot at first, but it does get easier. Have a look at coeliac uk for some information as they are really helpful and make sure you always spell it as coeliac when you’re searching for information as celiac is the US spelling of it and they have different information to us.
As above though, you literally only have to look for Barely Rye Wheat and oats (BROW). No need to check for anything else (even spelt, as spelt is listed as wheat now too). Also don’t eat anything that says it’s a may contain for those ingredients or a may contain for gluten or that it was made in a factory that handles those ingredients or gluten. And avoid labels that say, “not suitable for wheat allergy suffers too.”
the only exceptions to the above are if the product says gluten free, it doesn’t matter what the ingredients say, if it says gluten free it’s fine.
also anything with barley malt vinegar in is also fine.
barley malt extract can also be okay at a certain level, but the product would either need to be labelled as gluten free or coeliac uk would have listed it in their directory or their app if it is safe.
also be wary of cross contamination, she will need a new toaster and it needs to be a toaster just for her too. She can’t eat chips from the chippy unless they fry their chips in a separate fryer to gluten items. She also needs her own butter, jams, spreads ect.
I’d also say join some Facebook groups as they are super helpful too.