Cindi, if you don't mind telling, do you know the excuse for the ALJ changing your onset date? You're clearly not old enough for the Grid Rules to be a factor. Has it been 4 years since you've worked at all?
I concur that your monthly benefit is more important, but it is unfortunate that you won't be receiving any backpay. The bigger objection is that you'll have to wait for Medicare, which I'm sure you could have found a use for.
Some of your expenses also decrease by not working--smaller gas bills, clothing budget, lunches out, etc.