It took a long time to figure out as other things were going on at the same time. When I was 17, I had a severe stomachache in school and had to go home. SInce it happened about an hour after breakfast, we all thought it was breakfast that had bothered me, and I had eaten egg and a waffle. When I was a college freshman I ate some pancakes that were yellow with egg, and the attack that I got about an hour later was so severe that I ended up in the campus hospital. (dizzy, nothing was staying down or staying in me, etc).
That was the worst attack I've had, but I have had multiple run-ins with eggy items (but eggy items always have gluten).
Ten years after that, I ate something with soy sauce and got sick (diarrhea only). I now know that soy sauce has gluten.
Fast forward 20 yrs later and oats started bothering me, I was diagnosed with endometriosis which is a female disease and told to go gluten free (without celiac testing). After 2 years gluten free and for the first time, finding out about celiac, I got curious and wanted to be tested, not knowing I had to be on gluten for an accurate result. However, I did test positive 2 out 3 areas (genes and bloodline).
My dr had told me he had noticed the Irish tend to get it more, and I do have Irish in me. Two years after that test, I decided I wanted to know for sure, and with dr approval went back on gluten, but could only stand it 3 days. So while I will never know for sure if I'm celiac, I have so many things against me including all those reactions as a young adult to what I now know was gluten. I've eaten lots of eggy items since gluten free, and have had no reactions.