And in fact, a Social Security disability benefit pays the same rate as a full retirement age benefit. So you definitely don’t want to switch to a reduced retirement benefit at age 62.
When you reach your full retirement age, you will be automatically converted from the disability program to the retirement program. And because you are already being paid your full retirement rate, the money amount that both you and your daughter get will stay the same. So the switchover will essentially be transparent to you. What happens behind the scenes is that once you reach your FRA, your benefits will be funded out of the Social Security retirement trust fund instead of the disability fund.
So the fact that you have a full-time job is a pretty good indication that you don’t qualify for Social Security disability benefits. But if your conditions ever get to the point where you have to stop working, then you should file for disability benefits immediately. And if you do so, I suggest you spend 10 bucks and get my little Social Security guidebook called “Social Security—Simple and Smart.” One of the chapters in that book explains the disability program and offers tips on getting your disability application approved. You can get the book at Amazon and other booksellers.
I understand that your son isn’t working now. But in order to get “disabled adult child” benefits, you'd have to prove that your son was disabled before age 22. And you said he was working from the age of 16 on. So, his claim might have been denied because the records just didn’t show he was legally disabled before age 22.
Now please bear in mind that I’m just guessing why the claim was denied. You'd have to talk to someone at the Social Security Administration to learn more.
And speaking of talking to someone at the SSA, you should definitely file an appeal if you disagree with the first decision you got.
And here is another thing to think about. You said your son has been working since age 16. Assuming he worked at jobs where Social Security taxes were withheld from his paycheck, he is probably eligible for Social Security disability benefits on his own record. And to get those benefits, you don’t have to prove he was disabled before age 22. You just have to prove he is disabled now.
In a nutshell, I can tell you that you generally get a 9-month “trial work period,” during which time you can make as much money as you want and still get your Social Security checks. After those 9 months, if you are still working and making more than about $1,350 per month, your benefits might stop.
But as I said, there is WAY more to this topic than that. I suggest you go to SocialSecurity.gov and do a search for the pamphlet, “Working While Disabled: How We Can Help.” It’s a condensed version of that 100-page book I mentioned earlier.