They believe that the majority of the convention will either be sexual and/or generally too mature/inappropriate for my age. At the time of the convention I will be almost 16. I feel I should have a little bit of freedom to do something that will make me happy, and I also know that cons aren’t usually that NSFW, and if there are some NSFW things, they’re not just like the main attraction or anything.
I’ve tried explaining this all to them, but they won’t listen. This is the first convention that’s ever been this close since I joined the fandom about five years ago (at least that I was aware of).