@AlwaysTheGoodGirl I am in a very similar situation with my DD12. Here's what i wrote in a separate thread asking if there's downsides to diagnostic:
I cannot bring myself to putting the subject on the table with her as I know she will take it as a stigma, a judgement, a rejection, if I even suggest looking into it.
FWIW, we hesitated for ~4 years to really look into a diagnostic - if she is autistic, she masks really well. But the tantrums/shutdowns, the very deep need to recharge and chill for hours after school, the fear of over scheduling etc, alexythemia (inability to discuss/ identify emotions), extreme sensitivity to noise and smells, demand avoidance (and utter compliance at school)... it all seems to fit, including huge anxiety driven angry explosions when faced with new, sudden places to visit or activities (unless chosen by her)
But now that we've started the process, unbeknownst to her for now (as I want professionals to help us frame the subject in a way that enrolls her rather than alienates her) I feel like it's the right thing to do, almost like offering her a key that she can open the door with, when she's ready.
School have been very good. They indeed had zero suspicion, but did an in depth survey of the faculty for subtle markers of masked autism and nearly all teachers found elements that match the profile. As a result they will take her out of one of her regular lessons where she does very little because she's already bilingual in that language and give her 1:1s to see how they can customise learning support to her as she's also part of a "gifted" program. That way the intervention is under a "positive label" rather than "deficit - you need to be fixed" kind of positioning - BTW: I believe autism is NOT a deficit, but I fear my daughter would see it that way if we approached it from that angle.
I have a meeting with the GP (w/o daughter) next week to also discuss next step in the diagnosis route. At the end of the day, I want her to learn the coping strategies and emotional regulation, rather than the diagnostic itsself. And I want to learn to parent her better if indeed she has autism.
If you have an update of where you're (both) at @AlwaysTheGoodGirl I'd find a lot of value in you sharing your experience.