Tips for a first conversation: Dealing with 'voce' vs 'tu' confusion?

I have my first conversation with a native speaker from Porto coming up in two days and I’m terrified. I've been studying Brazilian materials mostly, but I know my contact is going to be using 'tu' and European verbal conjugations. How do I soften the impact of these differences during a live chat so I don't look completely confused? Is it better to just stick to one variant or should I try to mirror them? I am asking specifically about learning Portuguese, not a generic study routine.