I was diagnosed 15 years late, so this is kind of long, sorry.
My friends were the first to realize I seemed to have asthma. One ran track and the other was a tennis player. I couldn't do either and no matter how fit I was, I would always feel out of breath and that I felt I may die during and after I ran, though I never did I was definitely pushing myself to do things I simply could not and still cannot do. However, I am a strong swimmer and a singer. I never complained about my wheezing, shortness of breath, burning, stabbing lungs, or just godawful pain each time I had to run in gym or just playing together. Because society didn't seem to take asthmatics seriously until just ten years ago, and because I was undiagnosed for 15 years out of 19, I didn't take myself seriously and just thought I was really unfit despite exercising regularly.
In eighth grade, first we had a flu epidemic which got everyone sick in our tiny school and me with a fever and being unable to breathe with mucus clogging my throat and wheezing, my teacher asked me if I went to the nurse and got my inhaler, and I told them, no I don't have asthma. She then said "Bless your heart" and felt my forehead. I eventually went to the nurse and was sent home. Later, when I finally had the confidence to after 14 years, I told my gym teacher I got exhausted immediately. He asked if I had an inhaler, and I said no. So we both understood I had some shortness of breath and he'd just ask me if I was alright during each exercise. Even when I wasn't I said I was, but I didn't push myself to the limit.
High school I go to a public school instead of my small Catholic school, and I take the summer gym beforehand so I don't have to take it during classes. I pretty much had the same symptoms because I was used to it, I convinced myself I wasn't going to die even though it felt like it all the way through. On the pacer test, I did worse on the final than I did at the start of the course, and my teacher was just concerned, noticing I didn't feel well. The mucus clogged my throat and stopped me from breathing. Then later, in winter, I make new friends and well, I suddenly cough daily, nonstop, very loudly, in my friend's words "like a sick old man" as a fifteen-year-old girl. So eventually I go to the doctor and they diagnose me with mild asthma and give me a rescue inhaler, before they notice it doesn't fix the problem and they give me a daily inhaler. At first, the daily inhaler was intended to help "cure" my asthma, as they thought it wasn't that bad, until they realized it's worse than they thought and worse than I thought despite putting myself in danger every time I run for long (or short) periods of time. Now at 19 I finally see a pulmonologist and I finally get tested to see how well my lungs work and we're finally working towards a more accurate treatment. Thanks for opening this thread, it means a lot to me. If you ever need someone to talk to, you can always message me!