Can I show off my skills in official competitions against college athletes?

Only if you’re participating in an open event [an event not classified by level of education and where participants’ eligibility is not limited, except by geographical area], like a T&F meet [e.g., the Penn Relays]. Otherwise, competitions between high school and college athletes are NCAA prohibited. A college varsity team can’t compete in a contest against an outside team that includes high school athletes.

Scope out ncaa.org for more NCAA rules and regs.