https://developer.apple.com/wwdc21/swift-student-challenge/
See last condition:Applying
Build your Swift playground, answer a few written prompts, provide documentation, and submit.
To be eligible for the Challenge, you must:
Be 13 years of age or older, or the equivalent minimum age in the relevant jurisdiction (for example, 16 years of age in the European Union);
Be registered for free with Apple as an Apple developer or be a member of the Apple Developer Program; and
Fulfill one of the following requirements:
Be enrolled in an accredited academic institution or official homeschool equivalent;
Be enrolled in a STEM organization’s educational curriculum;
Be enrolled in an Apple Developer Academy; or
Have graduated from high school or equivalent within the past 6 months and be awaiting acceptance or have received acceptance to an accredited academic institution.
Have graduated from high school or equivalent within the past 6 months and be awaiting acceptance or have received acceptance to an accredited academic institution.
So, july 2020 graduation does not match.
But may be you meet one of the other requirements ?