Where can I get certifications for graphic design, is it worth it?

I am a 20 year old that lives in the U.S, and Collage did not work out for me. I am in a gray position of what to do for work and a need to move out. I have a stable job that deals with a bit of marketing although its only strictly weekends, and a waiter job for weekdays, although not ideal for moving out. I'm looking into Graphic Design Certificates as well as Marketing Certificates to land a well paying job in those fields without going back to collage for it. Its way to expensive, and the education system is not well fit for me. Due to that its why I'm looking into Certificates, as I feel like I do not have enough education or experience in these fields to be a proper higher. So far I have gathered these following web sights for Marketing Certificates that are with Google Skillshop and the AMA. I'm stumped for Graphic Design and if either are worth it. skillshop.withgoogle.com support.google.com/analytics/answer/15068052 ama.org/certifications