Have you completed the AQ50 online? It's a starting point and often one that you're asked to do to weigh up whether you score highly enough for assessment. (It scores in a way that tells you if you have Autistic traits qnd to what level)
Also, for me it was quantifiable. I didn't just feel a bit odd. I only ate 3 foods for the first 15 years of my life, I was painfully shy and hid from people, wouldnt stay over at friends / disliked going to peoples houses. I have many major sensory issues - I had meltdowns as a child if I had to wear certain things or had to go to the beach, would retch at the smell of school dinners cookkng while the rest of the kids were going "Mmm, mince!" I inspect food and will open sandwiches and take out the contents to check them. I massively prefer to be alone, I don't really understand banter. I have always had obsessive special interests. Had imaginary friends as a kid, never really fitted in with anyone. Hate socialising - I either clam up completely and people think im an arse, or I overshare. Detail. Constant detail required. Needing to know every aspect of a medical issue for example.
Once I put myself forward for assessment, I wrote my life story. My psychiatrist said he'd never seen such detail and that I have a complex symptom profile.
Yes, for me, it is definitely quantifiable. For me, part of my obsessive personality meant that I needed to know. I suppose that's when you realise if and how significantly it impacts your life.
I hope that all makes sense. Everyone is different, however, and will score differently on sensory / social and communication aspects. As the saying goes, If you've met one Autistic person, you've met one Autistic person.