The credits for work history is important and you can get a statement from the local social security office.

I've been working on and off since I was 16 so this wasn't an issue in my case but it is not an easy process. I was fortunate through work's disability insurance who hired an attorney who specializes in social security claims to help with the process. I don't know I could have done it with out them. It still was tough and the appeals process was lengthy besides the documentation and questioning process of your history. They said 99% of the time it does not go through initially and has to be appealed so be prepared for this, all a part of the process now. It was worth it.

I wish you much luck and remember to have patience.