Sorry to tell you this, but its unlikely that with the amount of panel submissions that are being sent in (I've been told its a pretty high volume)
That this late in the game its unlikely that your panel will be accepted especially if there is another one of the same variety being submitted. But that doesn't mean its too late to run a panel all together, especially if you do a different fandom panel and aren't picky about times.
(I've run the Black Butler Panels in previous years, and decided against submitting one due to the fact that someone else wished to do it this year)
My suggestion to you if you want to run a panel is to choose another fandom that your passionate about, one that doesn't have a panel so far this year, and submit that one instead. Or, just have fun attending the panels already being held!
Also, if you're still deciding on cosplays, maybe you could contact the other panel about being a different character on their panel? That way you could still participate.