There's a lot of information, both good and bad, here. I've written several stories on this for newspapers and magazines, and one thing people often miss is that you CANNOT "spot reduce," meaning you can't make fat go away from just one part of your body. No number of sit-ups or crunches will make belly flab disappear. You can firm the muscles underneath, but the flab will still be there until you diet/exercise it off.
I'm not quit clear whether you have actual fat on your belly or skin left over from a previous weight gain. Five inches off the waist isn't usually enough to leave a lot of loose skin. A year or so ago I lost 70 pounds I'd been carrying for years, brought my waist down from 44 to 36, and even in my 60s my skin took up the slack.