Nice to hear from you! I wish more folks would check in from time to time to let us know how they're doing.
AFAIK autism is not an easy thing to diagnose in the cases of high functioning people. Kids can be very good at masking it and trying to fit in, and then they end up slipping through the cracks. Hopefully this revelation will help you to better understand yourself.
My wife is nearly finished her studies to become an RECE so she has studied quite extensively about child behaviour and ASD, and our 3 year old will doing an ASD assessment next month. We've tried to learn as much as we can (though I am a bit behind my wife in that department; I guess I'm relying on her to be the expert ). There is so much to learn yet about ASD.