You have 13 years experience working for these guys, despite it being new unchartered territory you have a lot of experience to back you up that you should be able to apply some of to the new position! You know how things work even if you don't know exactly how things work specifically for this new job.

You can do this!

I'm in a similar position but far less experienced than you but I'm going for it anyway. If we both get the jobs we can share our funny fail stories together

Just remember it's human to not be perfect and to make mistakes. Everyone does it ALL the time, even higher up managers. We just have to fix it, learn from it and move on. And hopefully laugh about it later, much later... Haha...