>>98360728>>98360834It's not that the odds are low and that makes it hard. If she does the exact same thing each soft reset, (enter game, check mew, reset) she will be seeing the same range 20-30 Mews for hours on end.
In more technical terms, Emerald's RNG seed doesn't randomize, it starts from 0 every single time the game starts, then generates the pokemon based on how many frames have passed since the game started.