So I actually started out with WoK and WoR, and I moved both of them so much I read both within a school week, and WoR is my favorite. Even more so after reading Warbreaker and literally dropping the book when I realized the connections.
As of now, I'm caught up on mistborn, warbreaker, white sand vol 1, shadows for silence, and I'm almost done with oathbringer
And you should cosplay who you want to! Cosplay is all about fun and celebrating characters you love, so don't let your body type stop you. Just go for it and have fun!