Hi Della! I'm also on permanant disability (I have Parkinson's) and I know here in Jersey they have a program which entitles me to go back to work for 2 years without losing my disability. After that, my case would be evaluated and, only if it is determined that I can return to the work force full time would it be discontinued. Also, you can work part time indefinately as long as you're not earning more than $700 a month. I wouldn't think that returning to school would effect it since you're not earning money, but don't take my word for it. I'd say just make a phone call to your local social services office and they should be able to tell you over the phone.
A thousand standing ovations to you for choosing to be a nurse....I think that's great!!