Oh, Sweetleaf, Do it. If you land a job the learning curve will be steep, it always is, for everyone, no matter how simple the job seems to be. (Because we are expected to function in a new environment where we don't know where everything is and how stuff works.)
But you will absolutely love earning and having your own money. That you already know where you wouldn't mind working is a plus. For each place; formulate a statement about why you want to work there. Making such a statement is a selling point to the employer.
PS: I took a position as a supermarket cashier almost a year ago, after my business of 20 years dried up. It took everything I've got to learn this job. I am college educated. (The kids seem to learn it faster.) It's the best thing I've done for myself in a decade.
My best wishes and thoughts go out you in your new resolve. Best luck to you.