It REALLY won't be noticeable. Seriously. As a person who had K-con as goal to have my braces off by, but that didn't happen, it really didn't change anything, and cosplay wise, it doesn't change anything. I really mean it, don't change your cosplays cause of braces. I remember I was scared that it was going ruin my kumoricon, but it has no affect. Especially if your a girl, some reason my friend noticed that girls who have braces, people don't notice them as much, but for boys its a bit more noticeable but I really wouldn't worry about it, it only has positives, you can now cosplay characters who have braces ^^