Am I Overreacting to not wanting to go to a lock-in

For the past 2 years, my sister (7) and I (13) have gone to this gymnastics lock-in in our area. I liked it the first year, but the last year was really bad for me. I have moderate asthma to the point where my asthma attacks aren’t the worst, but are still painful (feel like this is the wrong word to describe it, but still). Last year, I had an asthma attack because of the smell and dust in the gymnasium, and since we were confined there, I couldn’t fully stop my asthma attack for the rest of the night. As I’ve grown older, my asthma attacks have been getting worse, which is why I had side effects last year but not when I was 11. A key thing to note here is that it has been getting worse in severity but less frequent overall. Because of that, I have developed a fear/anxiety towards my asthma, and though I try to not let it limit what I can do, I am genuinely afraid of it.

So this year, when my parents asked if i wanted to go, I said no. They decided they wanted me to go anyways because “I might have fun” and “my sister needs me there.” So here is the part where I probably overreacted. Over the past week, I have not been able to talk about the lock-in without being extremely negative and anxious about it. I also tried to convince my parents to change their decision by explaining the paragraph above to them, but I just got told to calm down, bring an air freshener, or my favorite of the night, this conversation:

“Mom: It can’t be that bad. Just put on some Vaseline to stop the asthma attack.

Me: Mom, Vaseline doesn’t stop asthma.

Mom: You don’t know that.”

Today (the night of the event), my parents finally relented and let me decide whether or not I wanted to go to the event. Obviously, I said no, and they respected my decision this time, but they have seemed so angry at me all day. I’m writing this before bed while my sister is at the event, and I just feel so guilty. I don’t think I did that much wrong, but I just really don’t want my parents to be upset with me. I was talking to my grandma today, and she said that “They didn’t make you go so you would stop being a bitch.” Now I feel really conflicted because I value my parents’ opinions a lot, but I also don’t want to put my health at risk.

So I ask you now, did I overreact?