@elianafranzenburg I think how you portray the word “ordinary” is part of the contest! I don’t think HSLDA (that fine organization, btw! They make great homeschool grad t-shirts in addition to providing legal peace of mind) is looking for an objective stock image. They’re looking for a creative expression of a very subjective word.
I won’t drop any other ideas for you, but I’d say start with what @bennett-family gave you, and then go to the HSLDA website and see what kind of images were submitted last time for similarly subjective words.
P.S. as a 2018 homeschool grad and 19 years old, I will say that enter these types of contests while you can. I’m super disappointed to say I just missed the opportunity!