I find that people don't often judge at conventions. We're all geeks and nerds and there for the same reason. If anyone is judging you, then they are really not worth your time and energy to think about it.
Try going to a few smaller conventions around your area. Going to big conventions can be overwhelming. Like I said ease your way back into it but doing some smaller cons first. Also try to go to meet up and gatherings for the series you are cosplaying from. You'll end up meeting people with the same interest, and it could help you talk to people more easily.
Eren Jaeger (Attack on Titan)
Mitsuru Kirijo (Persona 3)
Saruhiko Fushimi (K Project)
Shadow Yukiko (Persona 4)
Suit! Sarutobi Sasuke (Sengoku Basara)
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