Hi there Marishka, I see you are into much of the bigger animes. We may not be cosplaying in the same series (I'll be doing Ingo from Pokemon, then Japan from Hetalia, then an OC), but I think your best bet to finding a partner is actually hanging in the groups of cosplayers from the series. You're lucky since Black Butler and Naruto are big and widely cosplayed at cons, so it should not be all that difficult, yet it is your first con. Other people may be going alone as well, an hey, it may even be their first on as well. Just try asking around a bit, or hopefully someone would approach you! Good luck!
Japan (2p!, Beautiful World Cover Album, and White uniform versions)-HETALIA
Ingo/Nobori - POKEMON
Jean Kirstein-Shingeki no Kyojin