You have a great body. Trust me, at an anime convention remember that THERE WILL ALWAYS BE SOMEONE WORSE. Seriously, I've seen girls eight times your size going as Yoko from Gurren Lagann or Black Rock Shooter. You have a very good body, trust me, and you have wonderful legs. If you're short, they make up for it. In your photo you look nice and statuesque.
As for breast size, if it bothers you, all you would need is a padded bra.
You could easily pull off that cosplay, but just remember that you need to be comfortable
If the cosplay is going to make you feel self conscious or weird, then maybe you should try something else. But take our word for it, you're completely fine! You have a great body!