I don't think they'll ask too many questions about the lack of job experience when you're only 19. I got my first job when I was 18 with only baby-sitting experience. And I was terrible in my interview. I couldn't look the manager in the eye, and I kept playing with my watch the entire time. When she asked me "Why should I hire you over someone else" I sat there and stared at her. My answer? "I like your pizza." It was a pizza place. When I went home to tell my mom how I did, I told her I wasn't going to get the job and explained why. Everyone thought it was a funny story, but I was embarrassed. However, two hours later I got a phone call saying I was hired.
I think she knew I had anxiety because they kept me in the back the entire time I worked there. I only worked there six months until I found something I liked better. Everyone else was allowed to work in the front except me, even the kids younger than me. I never complained though. I was happier with that.
I was always told the: "You can't get a job unless you have experience" but I think when you're young they are are a lot more understanding about it. They know you had school and everything.
And for my first factory job, the ad said that they wanted someone with at least 4 years of factory experience. I had absolutely no factory experience at all, but I got hired. I think they like for people to have experience, but I don't think they will hold it against you too much. And I've always bombed at interviews. It doesn't get any easier.