Having lots of unfinished projects is common with people with ADHD. We tend to get over the initial excitement of starting something new and lose interest. In order to be actually diagnosed with ADHD you would have to be affected in other ways that seriously impact your life, but this is one "trait cluster" that a lot of people with ADHD share.
While it may be true that most people with ADHD don't finish things, it also true that most people who don't finish things don't have any disorder at all. They just don't finish things.
http://add-adhd.lifetips.com/tip/81525/adult-add-adhd/adult-...