Honestly, you really don't need to worry all too much. Namely if you're cosplaying a character who isn't very well-known/cosplayed. But in the case you are, just don't worry about it. The chances are that they're just a more experienced cosplayer than you, and with a few years you can be as good as them. I've seen some cases where if you cosplay the same character you'll avoid each other like the plague, but all I can say is just know they're as much of a fan as you and could be a possible new friend! Also good luck on your first convention!
-Holiday Matsuri 2016
-Joker (Alice in the Country of Hearts)
-Klaus (Story of Seasons)
-Madoka (Madoka Magica)