Continue writing the next sentence in this paragraph:

How to get your parents to let you go to an anime con
Be aware of your parents' knowledge of conventions.
Do your parents know what a convention is? Do they have the wrong idea? Perhaps they've seen something like it on tv, and they might think it's a festival of women wearing skimpy outfits and men wearing tights. Tell your parents exactly what a convention is if they don't already know.
Make sure they don't have the wrong idea! Be mature. Just as with asking for anything else, be mature with your parents.