My son was given a ASD classification right before the age of 3. They wanted me to place him in a self contained ASD class with all non verbal kiddos. They tried to tell me that everything he knew was rote memorazation. That he was hyperlexic, as well as having an IQ of 72. Instead we fought for a regular developmental delayed placement for prek. We hired a private BCBA, got control of problem behavior by implementing everything in writing for him. He was not hyperlexic. He could follow all rules and changes as long as it was clearly written on paper. BCBA trained husband and I, we signed up for every free ABA/VB site and also took web based classes. Once the aggressive bevaior was in check he took off. We did a VB prek program summer before K to brush up skills.
Fast forward to now.. Mainstream K,142 IQ, and the school which has never had a child in gifted before grade 3 is in process of figuring how to implement gifted pull out or enrichment for grade 1. Follow your gut with your child. If I had listened to the school system 3 years ago my son would be considered very low functioning at this point.