Oh you'll be fine. The more you talk about it, the easier it'll get. It takes practice though, and the first time saying it out loud, admitting it to yourself and another stranger, can be both stressful and rewarding. It takes on a new meaning, a new "real-ness" when you say it out loud, especially to strangers.
It'll be mostly a "getting to know you" session though. Just start talking and see what comes out. They may direct you, but don't stress it. If you need to talk about it, it'll come out of your mouth. 🙂