I nearly got diagnosed with autism as a toddler because I was ostensibly well-behind in speech development, until I suddenly started speaking a full year ahead developmentally around my third birthday.
Four years later I took the WISC-IV and did better on Comprehension (literally questions on social awareness) than the other verbal subtests, pretty much proving I'm not genuinely autistic. Though my overall performance pretty strongly suggested I have ADHD, but I never got diagnosed.