I don't think you need convention experience to become a cosplayer. I went to the outskirts of comic con and I didn't cosplay, but it was primarily because I wanted to know what it's like. So many people did cosplay, and although the only relevant thing I was wearing was a Pikachu t-shirt, I still got loads of attention from many people, cosplayers or not. I met a Pinkie Pie cosplayer over there, and we're both still talking. She's a great person. :D
2015 will be a year for conventions, as I'll be living in a big city and there will be a few nearby pony conventions, like Fiesta Equestria, DerpyCon, and Nightmare Nights Dallas (there are even more but I can't think of them), and obviously SDCC. Pretty sure I might not be able to attend all of the aforementioned. I'm already planning on cosplaying. Like I said about Discord, it's easy to fix a cosplay of him. I also have Rainbow Dash and Twilight Sparkle as options, and I wanna do Princess Cadance or Queen Chrysalis.