https://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolesc...
Unless you regress into severe Autism, it's very difficult for parents or even doctors to recognize Autism until they are atleast 2 years.
Also according to the schedule, there is no big dose around 2 years. After 18 months, there are not many doses on schedule until children are again 4 years.
Most parents complain about MMR vaccination that is scheduled at 15 months. My son regressed into Autism after MMR. It is true. I hope the world realizes it before more children get effected.