Depends on the player of course. I learned her basics in like 3-4 hours but of course none of that is any good until you practice against live players. Game has only been out a few days as well so we still dont know everything there is to know.
However, in terms of long term playability, Nu players will need to know all her extensive drive combos and when to use each one, as well as Rapid Cancelling her drive combos into her 6D, 2B, 2C, and 3C starters. You will also need to know proper timing for throw cancels, 5DD combo after throwing, as well as proper jump cancel timing for her anti-air combos.
However this can almost be said of any character for any player. Time will tell.