anyone who says that you can't get a good job because your 13 is bullstuff.
if you are good at something find a company that is like that and talk to them.
Child employment laws stop you working at a young age. Usually it's limited to things like 5 hours a week ages 12-14, on say a paper round. You don't tend to be able to do part time or full time employment until age 16 or 18, depending on location.
Companies that hire you under those ages are breaking the law.
That said often places will offer you small jobs for cash in hand. Try asking around local small, family-run shops. Maybe a bar/pub collecting glasses, or collecting balls at a golf course. All prospective small time jobs.