When I code in anger I use Julia, but that isn’t what I’m recommending for her. The obvious answer here is python, but I wanted to make sure I wasn’t missing anything.
On the other hand, Python appears to have good libraries [2][3] for CNC-control related programming.
Finally, if Julia is what you're most comfortable with and enjoy, don't underestimate the importance of that either.
[1] https://en.wikipedia.org/wiki/AutoLISP [2] https://pypi.org/project/bCNC/ [3] https://pypi.org/project/pycnc/
Don't get us wrong, let's get it analogue: we're assigned to serve or cook to someones just well to satiate the hunger, as we have little versatile skill in doing it what we need is the urgently simplest skill, such that is know how to make dough and bake while keep clean work, and the rest ones will be achieved on the fly further as we're working next
That very basic urgent but also simplest one, is C up to intermediate or upper basic
Then some linear data application or PL, Julia, FORTRAN, Mathlab etc etc accordingly to the most suitable stance
Anyway, Julia is my preferred language, and it has the depth to teach you widely useful concepts. For example, I'm now learning C++, and my Julia experience has been very valuable.
Python, of course, is the safe, mainstream choice. (If you want her to become a weirdo or outcast, you might of course consider C or Fortran;)
Python in the cases I`ve witnessed is wont to hamper the user’s rate of learning.