I was super nervous when I first signed up for Italki. It took a lot of building up to get me to even message a teacher. Although not in person, there was still that same anxiety.
Maybe reading over my old thread would help?
The first one is always the hardest, it definitely gets easier with each new lesson.
Don’t worry about making mistakes, you’re learning! Their job is to teach you, so they expect you to need help. And besides, I’ve found the more mistakes I make, the more I learn. If you’re automatically perfect at everything, then you have no room to grow 
Best of luck! Let us know how it goes :o