Most of the exercises in the course are autograded, but some exercises require manual grading by a CodeHS Tutor. For these exercises, when you submit the exercise it will show up as Yellow meaning "submitted." Once a Tutor grades your exercise, it will either show up as Green for "passed," Blue for "Functionality OK," or Red for "Rejected."
The Amusement Park exercise is one that requires manual grading. You should receive feedback from a tutor on your exercise soon!