There is no need to set a starting point for the introduction of calligraphy. If there is a threshold, I think it needs at least a little aesthetic level to know what kind of words are good and what kind of words are ugly. This can get twice the result with half the effort
It doesn't matter if there is no aesthetic level. Finally, you can get started, even if you can't become everyone, at least the words you write can be above average.
The most important thing is to keep practicing for ten years.