It won't hurt anything to go gluten-free now, except the possibility of getting a diagnosis of celiac disease. When i went gluten-free, it seemed like the initial changes were spread over about 6 weeks. I had gut spasms for that time. And other changes, all for the better. Initial recovery from celiac damage can take up to 18 months, so it can be a slow thing. Some people get better much faster of course, because we are all individuals and not identical.
Going gluten-free for celiac disease is a lifetime commitment though, and some people have a hard time doing that without a diagnosis. Even minor amounts of gluten can cause us to react, so it is best to eat a very simple diet of whole foods at first. Avoid dairy and processed foods. I hope it works out for you. I know some people with Crohns disease eat gluten-free and find it helps them. Gluten is a tough thing to digest for all people, but most don't have an immune reaction to it like celiacs do.
Honestly, I would not trust the school to provide a gluten-free meal except for fruit, salads, veggies, etc. I sub in a school cafeteria and I swear everything is breaded or on bread. Utensils are shared. They're very clean but unless you have a very knowledgeable person in there, I just wouldn't chance it. I found a slim Jim type snack that says gluten-free on it. If you want to give me your email or FB account, I can send you some very valuable info on 504's though. They carry the student right through college. I kept a copy of what a friend wrote about her daughter being in a sorority and just how the 504 helped immensely. But, I would definitely get one and still be prepared to pack a lunch. All our meals are delivered frozen and we just hear them up. If your school actually fixes food, that's different.
Oh, I would suggest providing gluten-free goodies (e.g. Candy) or even a frozen cupcake (kept in the teacher's freezer) in the event of a party. My daughter's classmate is severely allergic to peanuts. Her mom did that and Abby was never left out! 😊
Welcome to the forum!
I noticed you said you have been avoiding wheat products. That's good, but are you avoiding rye and barley also? Wheat, rye, and barley are the 3 grains that cause reactions in celiac patients. About 10% also react to oats.
If you haven't had the full celiac antibodies test panel, it might be worthwhile getting that done now. The ttg is just a basic test and is generally followed up by an endoscopy or the full celiac panel.
I wouldn't worry a lot about getting cancer. That doesn't happen often.
It is possible some of the other grains you might be eating are contaminated. A group did a test on several off the shelf products a few years ago that would not normally be thought of as having gluten and found some actually did have low levels of gluten. Things like corn meal for example.