I went to my first convention just last month and it was absolutely amazing.
I cosplayed Sealand and met a group consisting of a Fem!Italy, Fem!France and an America. (Italy and France were from their respective countries too!)

We had a lovely photoshoot later on, everyone took pics, so that was also nice.
FFFFF-

THE DEALER'S ROOM. Amazing. Just really amazing. And also very expensive.