I don't know what to do when I grow up!?

I am only 14 and I have to choose my "o" level subjects very soon. Now I am confused about what I want to be when I grow up!!!!!!!!!!!!!!!!!!!!!!!!!!! And I don't want my judgment to depend on some fascination of the unknown because I changed my mind a lot over the days and I still don't know what to do! I know that I have to do A LOT of research on what would suite me because I HAVE NO AIM! So can you give me some good career counseling websites? I don't want to do something typical but I don't want to do something wild either. Well actually I don't know! where do I find a website for JOB DESCRIPTIONS? I HAVE NO IDEA WHAT PPL DO IN A OFFICE! AM I DUMB? SHOULD I BE WORRIED?