People of all shapes can cosplay. I just saw a hexagon in a Hatsune Miku cosplay last week.
Anyway, glad to hear you've decided to start cosplaying. The people here are wicked helpful and love to give advice from experience, so don't feel shy about asking questions.
facebook page // nh/mass cosplay events
Next event: Summer Matsuri
COSPLAYS IN PROGRESS
Umbreon (Pokemon gijinka) - Constructing
Gaius (Fire Emblem: Awakening) - Buying stuff
Vaati (LoZ Minish Cap) - Planning
Soren (Fire Emblem: Radiant Dawn) - Constructing