I predict they run 16:45 5ks and 4:45 miles in high school. At their peak trained as a miler they could run about 4:12, soundly demolishing Dibaba's record. Discus.
Hopefully the Webb parents never show this thread to their daughters so there is not undue pressure as young athletes to perform with outsized expectations.
I don't think they check LetsRun though, so have at it!!