You’ll never feel fully ready for the new job, school or city. Ready usually shows up a month after you start.

Readiness is produced by doing a thing, not acquired beforehand. The confidence you are waiting for is made of experiences you can only have once you have already started, which is why the feeling never arrives while you are preparing. A month in, you will be competent and the question will have stopped being interesting.

Pick the thing you have been getting ready for and set a start date in the next two weeks. Prepare the minimum that is genuinely needed and accept the rest will be learned in place. Expect the first fortnight to be uncomfortable and not to mean anything.