Assessment looming and I'm getting anxious

I was so excited that my assessment was drawing near.  This week they contacted my older sibling (that I gave them as a reference) for information on my development history.  I wasn't expecting that to be a separate thing, got into a panic and emailed the centre asking for more information. Which to be fair, they responded to promptly and in a very reassuring way. But it did make it clear to me how much this process is causing me stress.  I don't usually notice my stress levels until they hit crisis point, but I'm making a deliberate effort these says to check in on myself and observe my physical state and my reactions.

I should find out my assessment date in the next couple of weeks.

I'm trying to gather as much information as I can, and use my calming methods, but I feel like I'm about to have my whole life and my identity put under a microscope and evaluated and it would really help to reassure me if a few people could just say that they know what I'm going through and offer some emotional support in whatever autistic form that takes.