I guess in the process of trying to diagnose yourself, you might notice more symptoms that you previously didn't realise were not normal. However at the same time, sometimes it can be hard to associate actual behaviour with the description of the symptoms. As in, you'll see the descriptions but you don't know how it actually shows, what kind of behaviours count towards it. It's best to be diagnosed by a professional, but researching and thinking more about your own feelings will help you have more to say to that person; this just makes a diagnosis easier.