This article, seemingly dated 10/28/16 says she was 14 as of then.
http://www.malibusurfsidenews.com/high-school/10-questions-claudia-lane-malibu-high-school-cross-country
Maybe they were wrong, or maybe she just had her birthday. I live in CA so I know that many freshmen who have birthdays in the fall enter at 13, so for her to be a soph. at 14 is totally reasonable, as long as her birthday is at least before the end of the calendar year.
I was thinking the same thing about Baxter (though she's not done yet) and Stamps. I read some of the Washington Post article and am quite interested. I've seen some of the same.
I wonder how to respond. I don't want to give my female athletes an excuse not to work hard and improve but I want them not to get discouraged if they go through a backward phase. I finally addressed it briefly with my varsity girls this year and tried to say that not everyone improves like they'd hope, and for girls, for "some reason," it's easier for them to be spectacular as a Fr. or So. and everyone to have high expectations. But it's just more of a role of the dice for girls than the guys, and some girls don't improve much and sometimes it's not really their fault--their body is getting ready for something more important than running. (Being a mom.) But that doesn't mean that after that they couldn't still improve, so it takes perseverance and endurance year to year.
It is hard as a coach to see a girl go backward and not be happy with her times race after race. I try to encourage and still motivate, but you can't really say their bigger hips and extra weight are the problem. I'd rather they run slow than end up with an eating disorder.