Hi, I think that
everybody has feelings like that when they're getting started. Everyone has something about their body they don't like. Or, they just wonder if they'll measure up. You'll learn very fast that swinging is full of normal people with average bodies, each with their own little flaws - and each with their own beauty, too.
Have you looked through swinger's profiles on adult personal ad sites? That's one way to see all the different body types that are in swinging. You'll see every kind of body. Go to any club function or meet-and-greet, and you'll see. Swingers come in every age, shape and size. You have a little pudge in the usual places - don't we all!

You'll be fine, I'm sure.