Wait, what do you mean by group? You should always be able to say whatever you want whenever you want. Who cares if people laugh at you? It just means they're too self-conscience about themselves. And who cares if you say the wrong thing? At least you'll be saying something. You have a voice, so that gives you the right to use it to speak your mind and face your fears. Honey, believe me, you're not fat. You're just fine the way you are.
And if it makes you feel better, I'm going through the same stage. :P
As would I.
<3