Starting a new job in one week. I'm kind of nervous, because I didn't expect to get the offer, but I did. So I'm in my last week of my current job. I have no issues or problems with my job, I love the way things are run, the people, team I work with, and processes in place. 

However, another offer came to me, one that I did not think I was going to get, but interviewed for, just for experience. To my surprise, despite my experience of only three-months in my current role, they decided to offer me a promotion and job salary bump. I'm floored.

I trust their ability to suss if I'm the right candidate with the correct qualifications, but deep down, I also know I have bad anxiety. It's akin to them finding out I might not be whom I say I am.

I haven't had any reason to lie, and because I went in the interview with just honest interests and intentions to find out more information, I was genuine and only truthful about what I know and don't.

However, it is also the first time I'll be a senior and as well, manage a lower level report. They won't report directly to me, but be under my guidance and tutelage.

What's the best way to approach the new job with profound confidence and how should I set myself up for success so I can ensure I don't get canned?