I worked helping with people with learning difficulties for about 6 years and kind of heard of it that way. I have always been uncertain what I wanted to do and looked into loads of professions - speech and language therapy, social work, even teaching as well! I still wasn't 100% sure when i applied for the course, but I have done two placements so far and found them very interesting.
My first placement was in paediatrics actually - over here the OT's do lots of work with kids with co-ordination problems (more commonly known as Dyspraxia) and handwriting difficulties. Have you come across OT's in your work?