Molly, I'm in the same boat as you -- Please let me know what you find out at your local Kindergarten class because I'm very interested.
I deal with GT denial on almost a daily basis with both of my DD's, 3yr9mo and 17mo.
DD3 phonetically sounded out her first word at 2.5. By that time, she knew many many sight words as well.
She has quickly gone from reading random words, reading the super-easy readers to now reading Clifford books almost fluently. I'm assuming this isn't normal, although it's easy to psych yourself out -- especially when a lot of people on this forum have kids who read really early.
Good luck to you and congrats on your DS's reading skills!