Hi Marcus. After reading your post, I think I'm likely right that your employer recognized some very good traits in you. Their offer seems to reflect that. You are clearly very honest and open. Many people who don't retain everything say absolutely nothing. And many of those are people without any mental health issues of any sort.

I have initially struggled in brand new jobs or with new projects in the past. Sometimes those that struggle a little in the beginning, go on to work harder than those who didn't, eventually bypassing others in terms of quality performance or what they can offer beyond.