The international standard of U18, U20, Senior, and Masters makes the most sense to me. Age records I am not a big fan of because they encourage training hard at a very young age, which can sometimes seem to stunt long-term progression. Off course it sometimes works out, but even Jakob didn't set his first age group record until he was what, 14? And didn't become a top pro until he was 17. U18 records are mostly run by 16-17yos, which I think is a fair age to be training seriously.
If you go by that standard, the U18 1500 record is 4:04.62, by Cain.
The U20 1500 record is 4:03.39, by Efraimson.
The U18 mile record is 4:28.25, by Cain.
The U20 mile record is 4:24.11, by Cain.
Obviously 1600 records are not really internationally accepted, but Wiley's 4:26 would be the U20 record. No idea who would have the U18 record to be honest. Sadie's 4:31 is a great time regardless, and puts her on the map as one of the fastest U20 Americans ever (not eligible for U18 though). A sub-4:03 time seems possible in 2024 or 2025 and would cement her as an all-timer. Let's hope she has a better professional career than the other high school record holders.