Freshman year is a level change, not an age change
The 100m field goes from one grade to four grades at once. A time that won middle school meets can finish sixth in a JV heat. That is not evidence anything went wrong. Most varsity sprinters were nowhere near varsity as freshmen and were still varsity by junior year. The same step change hits the field events, where a 14-year-old's long jump is suddenly measured against seniors.

