I may or may not have an interview this week

I've never had your traditional interview. My first interview was a working interview at a dog kennel and then a few hours later was asked some basic questions like tell me about yourself and how do you feel you did today.

My second one was also a working interview. I was asked to tell them about myself and what days am I available to work.

I'm 21 and have never been able to get a job since I dropped out of school my senior year (I was 19, so two years ago). Since then I've been doing little side jobs and that's about it. I've never had a normal interview so I wouldn't know how to answer anything.

I have very bad anxiety and I'm really worried I'm going to stutter and stumble over my words