I'm 40. In July '09, I was diagnosed with Graves. In June '09, one month prior, I went to my family doctor for a routine physical. My bloodwork showed hyperthyroidism. I thought, "Hmm...wonder what that means?" :)
I didn't know much about it, but I had had a weird symptom for a few months prior. I felt like I had electricity running through my body and felt "antsy" and irritable.