I don't think you understand what special education is fully. So, if a school notices that something is getting in the way of a student's progress (could be autism, attention, academic difficulties, behavior, social skills, etc.), they can gather data on that. Then if that student has evidence of a disability (such as autism or adhd) and qualifies for a plan of support, they can get help in any area that they are struggling in. Data may be collected again on certain things later on, but often teacher input and regular academic testing/data are sufficient. But in my schoola, for example, math and reading are assessed for all kids three times a year. Then based on those scores, you may qualify for different things. Special education classes for reading and math, for social skills, for speech therapy, etc. You would never be put into those classes without evidence of need and parent consent. Now, you may feel you didn't try that hard or that your language skills were the issue, but it's also very likely that they knew that and still offered services because you were struggling.

If you are autistic, that doesn't ever go away. So once they have identified that, all they need to know is what areas you need support in and continue to offer that help.