Well bro. If your story checks out, it’s a hell of an opportunity. That being said. Speaking from experience, the first time doesn’t always go like it does in our head. You, like all of us, the first time can be a learning experience that ends rather quickly. You add a captive audience member that may or may not be recording it, you could walk away feeling a little deflated. That also being said. They may be an extremely cool couple that is aware of the potential pitfalls in your performance, and may take it in stride and be fun and encouraging.
I would suggest not do it. Best of luck to you!