Exactly when did you notice one of your kids had autism?

My son was not 2 yet: My son was diagnosed before his second birthday. Early on he did not engage us with eye contact and later we noticed he would not respond to his name. We also noticed some repetitive behaviors, no imitative skills and abnormal play skills. That was 13 years ago. Today at 15, he still is a person with autism, however, through care teaching using applied behavior analysis, he still makes gains.