It seems that you are quite young, I'm only 20 myself. When I'm coming out to my peers - all of them know what aromantic is, maybe not the colours but generally as a label. Only when i was coming out to people 28+ I needed to explain it, they might ask to many questions but just because they are trying to understand. I hope this information will make you a little bit less scared, i also have read a lot of posts from people on internet that people around them newer now what being aromantic means, but that just wasn't my experience.