My brain tumor symptom came on Feb. 15, 2015. I was playing in a soccer match with my team -- Express -- at Meyer Park in Spring, Texas. I burst though our opponent’s defense and calmly knocked the ball home for a goal. Seconds after the restart, I headed the ball.

What happened next was the first of multiple seizures. After passing out, I woke up on a stretcher as I was being put into an ambulance. This was not part...