What are my chances of getting hired?

I have a job interview for a Seasonal Stockroom Assistant role at a retail brand, semi posh one (imo) and I wanted to know if anyone knew the chances of me getting hired since I’ve been anxious about it. I don’t have proper-proper work experience I just put some random odd volunteering I did one time. My interview is on the 16th Sept and it’s also only 15 minutes long. Is that a bad thing? Should I be worried with how short it is? I’m shitting bricks mainly coz I really need this job and places NEVER get back to people. This is also my first job interview face to face so if anyone has tips please do tell. What are the chances they hire me on the spot? That would put me at ease rather than anxiously wait for them to get back to me.