Athlete's effect on other students?

Another girl at my DD’s high school recently committed to play soccer at Princeton.
Would this affect her chances of getting in because Ivy’s typically don’t take more than a few (if any) students from one high school or are athletes categorized in their own section and process?

Typically, athletes are in their own league for college admissions. However, it might also help you to look at your DD’s school’s matriculation list from the past few years, and see how many students got in.

I doubt it will have any effect on your daughter.

When you look at Naviance, one of the things you can’t know is what hooks other applicants had. So if, for example, your school is a soccer powerhouse and regularly has most of the senior players recruited for college, the stats for those players are irrelevant to you. Unfortunately, they are also indistinguishable in Naviance from the non athletes.

But colleges don’t have quotas for high schools.

Will have absolutely no impact. The colleges will understand. The athletes often have a separate admissions officer who reviews their applications.