Brendan - - there is a mythicon meet-up planned for Puyallup, WA (just south of Seattle), but I see that is about a 3-hour drive from your home town.
As far as hosting a MythiCon event at your age, first please confirm that your parent or adult guardian could be an active participant / support . . . here are the host ideas and suggestion links plus a page that describes what this is all about.
In previous years we've had HOSTS of 12-13 year olds (with help, of course) so I don't see how any committed MB should be disqualified on age alone so long as they have the needed support for transportation and other concerns. Actually, the original idea was from a 13-year old K-La V. (LANDSHARK) and her friends, but her Mom had to provide the ride to the mall in Syracuse, NY where they celebrated