What starting early actually means
It means direction, not intensity. A freshman who has picked two things and stuck with them is in a better position than one doing eight, because depth is what becomes interesting later and breadth at fourteen usually becomes nothing at all.
It also means the transcript. In most US high schools, ninth-grade grades are on it. A weak freshman year is entirely recoverable — an upward trend is a real and recognised pattern — but it is easier not to have to recover.
The rest of "starting early" is administrative and takes very little time: keeping a running record of what your child has done, when, and for how long. Four years later that record is the difference between a well-supported application and an evening of trying to remember.