First Zoom call with a native Croatian speaker—how do I bypass the 'freezing' phase?

I’ve done duolingo for a year, but I’m a total false beginner when it comes to actual output. I have a session booked with a native speaker soon and I’m terrified I’ll just go silent. I’m thinking about using Chickytutor.com to simulate a real conversation beforehand to build some muscle memory. Has anyone used an AI tutor to bridge that gap between reading comprehension and real-time speaking?