You know when we all ask questions like "Is my XYZ worry crazy or what?"... Well, that's anxiety for me right there. All the XYZ's are fair game for us to worry about, because well.. we have/had social anxiety and so every worry is shared by one of us if not all, we can understand the irrational because there's the crux of our problem. And yeah!! New jobs/interviews - those are anxiety causing things for most anyone I have ever known - like SA people or not.
Saying your worry out loud to us is great, and to yourself. Recognizing the ANT. And then you came back with some rational self talk in your response. Way to go. And try to get back to that rational train when you are at your job and do get anxious because hey, that's probably going to happen to you, and to anyone starting a new job, and hey, that's no big deal! You're choosing the healthy path. You do get better and stronger by facing these things with the therapy. Therapy alone in a room forever and ever doesn't get us into the real world.
I've gone for long stretches of changing jobs, working from home, work gaps (that's 3 euphimisms for unemployment right there!)... And coming back to a job involved a period of adjustment and discomfort for sure, but it was always good that I did it, good that I got back around people, and started to flex those "social" muscles again that had kind of weakened but not died just from general disuse.
Congratulations on getting the job!