OH yeah.
Yes, you are risking failure. That's what going outside one's comfort zone does. OTOH, you could stay doing the same job you KNOW you can do, and stay stuck.
I think the key is to go in with the right combination of humility and confidence. You go in willing to learn the ropes with the new job, ready to ask questions of your colleagues and bosses, but with the confidence that after the initial learning curve you can master the skills.
Sounds like you are someone that the interviewers see as a person with the potential to succeed and be an asset to their organization--and they're right!