I graduated from the University of Oklahoma School of Visual Arts with a BFA in Art, Technology, and Culture with an emphasis in motion graphics. I have been freelancing for around 2 years. I normally work with video and 3D design, but creating a still image for your son's graduation is entirely within my abilities.
I think it is awesome that you are doing this for your son. Also, I am a big J. Cole fan as well, so this will be great for my portfolio. I will treat is as my own pet project!
I would provide example images, however I have not ever worked on a graduation cap. I have worked on countless images for print, so I understand the resolution requirements for an image to be printed to fit on a graduation cap.
Thank you for your time. I hope to hear from you soon.