I really suck at being a human being?

This isn’t really a period or pregnancy problem, just something I want to get off my mind. I really suck at being a functional person in society. I’m 19 going on 20, but most people think I’m 13 at the most. A lot of people say I’m pretty despite looking like a freaking child but I feel like that’s honesty the only good trait I have. I feel like my mental growth is so much slower than my peers. I still think like a middle schooler would, I’m always distracted and playing video games and daydreaming and doing... nothing. I’ve never had a job before despite really needing one. I’m so scared of authority figures like a kid would be so I refuse to go to Interviews. I tried going to an interview once but threw up from nervousness and went back home. I have no interests or hobbies - everytime I start to learn an instrument or watch a show or get into a band I get really bored and give up. I’m smart at school but not really smarter than anybody else. I’m just bare minimum average-smart. I SUCK at talking to people. The only people I talk to on the daily is my best friend, my roommate, and my immediate family. I have never raised my hand in class or even talked amongst a large friend group. My parents kept me inside all my childhood so I never gained social skills. I don’t even know what to say to people. I have so much social anxiety that eats me alive. And even when I’m not scared to talk to someone, I have nothing to say at all. I just make every conversation awkward and forced. I’m getting to the age where I have to get a real job, but I feel I am so young for this world. I just wish I could be a kid forever. How am I supposed to be an adult when I can’t even talk to people or do anything right?