I should say that it's nearly impossible to get a job that somehow correlates with your desired subject without any connections at 18. Even if you apply for an easy job, you will most likely get rejected from 90%-95% of them pre-interview. I recently got a job without any interviews, but this was all down to luck. I am applying for Mathematics + computer science and getting a job or part-time job in that field is very unlikely without a degree. So, I applied for a job to get some work experience because nearly any work experience is valued and to earn some money. Right now I am on a gap year.