Well, I might as well volunteer my personal experiences since it is relevant to the thread.
When I was around 6 I was taken to a specialist who suggested that I might have a mild form of dyslexia. At the time, my parents never told me.
Over 10 years later I got an A at English AS. So do I have a mild form of dyslexia? Perhaps, as I still make the odd spelling mistake. Still, I'd rather have not known and tried to persevere with the english language, than be told I might have dyslexia, give up and not have got anywhere.
For others with more extreme dyslexia, the conclusion drawn to might be different.