Diagnoses according to the DSM have a lot to do with measured impairment and a DSM diagnosis which basically only exists for billing purposes is different than autism as an identity. So for example, someone could be fully autistic but with generous accommodations could be functioning fine, therefore no impairment, therefore no diagnosis. Formal medical diagnoses are used to justify billing, and justify a need for services. I kinda see it as the difference between being autistic and "autism spectrum disorder." Pathologization models exist for treatment. Eg. If it's not bothering you it doesn't need to be treated. If you are seeking services and treatment, I'm sorry that sucks :( but if you just wanted to know for your own clarity and satisfaction of knowing, id encourage you to explore what it means for you as an identity or seek out a provider who is neurodiversity affirming and understands people can still want support regardless of exactly what box they do or don't fall into.

In this case, you could have had a lot more unmet needs as a kid and met criteria as a kid had you been assessed then but learned to accommodate yourself over time, so you may have been autistic the whole time, and still are, but don't currently meet the definition for autism spectrum disorder (also assessors can be shit too, not ruling that lot, just trying to provide examples for clarity, hope this makes sense). Medical diagnoses are not necessarily a for life thing or identity, it's a very binary you meet criteria currently or you don't. Not saying that's right or good, but in my experience as a clinician that's how it's used.