Does anyone have any experience with Goodwill's Job Center

You should write a resume and cover letter, then start handing them out wherever there's an entry level position if you haven't already. Job Centers are only one possibility, and if you rely on it alone it could take a lot longer to find a job. Most places understand that you're nervous, especially if it's your first job, but you have to leave that anxiety at the door if you expect to earn a living.