The first sign that I had something occurred 9 or 10 months before the first flare. On a routine blood test my platelet count dropped and my internist sent me to a hemotologist. Many months of testing and testing again produced no explanation and my doctor speculated, by process of elimination, that I might have lupus. I also had mild anemia.
In retrospect, I had mild anemia and low platelets for at least 15 years before the first flare so the disease was lurking in the dark ready to pounce.
After the first flare 3 years ago it rapidly progressed and within a few weeks was able to confirm that I had lupus. He felt I had more than just lupus and thought I had mixed connective tissue disease which was confirmed about 2 months later.
Auto immune diseases can be asymptomatic for a long time, even years, and then become symptomatic after some trigger pushes it over the brink. An earlier trigger pushed it to the edge but something later on pushed it over and you became symptomatic. I was lucky to have had a blood test just when my platelet count dropped. Otherwise, it would have been a complete surprise.
Bill