Most Helpful Guy
I'm a bit confused , if you're fat , then you're fat . What difference does it make whether you have wearing a shirt or not . It's not like when you're wearing your shirt , you like you have a six pack and when you take off your shirt , you suddenely become fat .
Most girls don't care so much about your body . The ones who care a lot of physical appearance are the girls you have to avoid . I'd say just go for the pool party . If you're very very uncomfortable then back out , but otherwise just go.