I have lost 70 pounds and was worried about this. I have been "dry body brushing" - which takes of the dead skin and encourages new skin renewal. Using cream and/or oil every day and exercising. So far - fingers crossed - the stomach is ok - bit of dimpling but that's all. The tops of the legs are a bit wrinkly - but this has got better over the last month. Arms - well - bingo wings, but then so do a lot of people my age. I am exercising as well (lifting weights to try and build muscle and tone - to fill in gaps the fat loss has left).
I think patience is the key, they say it can take up to two years for the skin to "re-adjust" to a new shape. If you look after your skin and exercise you can minimise the flabby skin. By the way, I am pretty old too

" Success is what you make it, there's no better time to make a change than the present."
"Wherever you go, no matter what the weather, always bring your own sunshine. "