Sort of? I was tested as a toddler and told it was on the borderline of being diagnosable. My mom decided against diagnosis at the time but I was later diagnosed as an adult. While it is true that autism must be present in childhood, symptoms can become clearer later in life because social and other demands increase. The DSM literally says that symptoms may not fully manifest until demands exceed capabilities. Also sometimes doctors are just wrong and/or biased. Have you tried explaining these?