I do understand, especially because you really are giving up control over your body in a way you wouldn’t normally when you have surgery, especially if it’s under general anaesthetic. A lot of people do find that loss of control quite intimidating, especially if they are usually healthy and haven’t had much experience of this sort of thing before.
And yes they don’t tend to explain much in pre-op! Especially these days (prepandemic you’d often have been able to have a good chat with the surgeon about exactly what is proposed and why and all the ins and outs of it, but that seems to have generally gone out the window). Even I was surprised at how limited the information was beforehand, and I’d probably have found it a lot more daunting if I didn’t have insight as to how it all works from being a junior doctor.
And yes it’s going to be a total change in your usual routine whatever happens but I can see not knowing roughly when it might even happen is particularly challenging for someone with possible autism.
So please do tell them that you suspect you have autism but are usually healthy generally, and so you are finding the lack of control and change of routine and not knowing what to expect particularly anxiety-making and it would really help to know where you are on the list and if possible for your procedure to be done sooner rather than later. And then they can at the very least keep you posted as to what’s happening and whether anything looks like it might change through the morning if needed. I promise they won’t laugh at you or think you’re trying it on etc. Your level of anxiety over this is unusual and makes a lot more sense looking at it from the angle of possible autism.
You never know, you could end up first on the list so try not to panic now and overthink about worst case scenarios.