They usually say you should wait until late 20s, your eyes should level out (mostly) and then it should be good for 20 years or so.. maybe?

Also, keep in mind "vision habits" affect myopia and can be relearned. It's really like KIDS should be taught HEALTHY VISION HABITS and there is really not much knowledge about this currently, although in previous decades there was a book by "Bates" and it was famous for teaching good, relaxed vision habits. I actually took a class, and it taught to keep eyes relaxed, take breaks, use wetting drops, and focus in a relaxed way, look way from the book or screen, and focus far away often.

And I FAILED to mention, Presbyopia, where as a person ages, in their 40s-50s the eyes will harden, and we start to need reading glasses at that time, and I'm just starting to get where I can't read close up without reading glasses, but can still use the laptop or phone wihtout reading glasses.

So nothing lasts forever, but it was a great couple decades I've enjoyed now..