It's useful if you can help with all the initial installing and configuration that is boring and confusing. She can learn that part later.
I don't like languages where 1+"2" is not an error, so I guess I recommend Python. Python is easy to install, but downloading additional packages is not so obvious.
A "clone" of Stardew Valley looks like a nice project. I had to google it, it's a 2D pixel game, but I'm worry that each object needs too many verbs and she may fall into a OO trap.