I would be inclined to start a youngun with an older generation prosumer point and shoot, preferably one that takes normal AA batteries so that oodles and oodles of batteries can be provided (NiMh rechargables or those zooty new lithium ones that pretend to be normal AA's) so that you're not battling constant new-old-stock problems with eBay batteries that already arrive degraded. Something like a PowerShot SX120/130IS, maybe.
The battle you're going to face with the current crop of whippersnappers will be the, "why do I need a clunky old granddad camera when my smartphone/tablet already does everything." Demonstrating the significant zoom capability of even a dinky midrange camera from a decade or more ago to frame distant and interesting subjects (i.e., animals) is usually sufficient. Long exposures are usually pretty captivating, too, like the ability to take pictures of the stars. These are not coincidentally the two things that smartphones are rubbish at, and therefore are the most interesting.
Mountains, birds, cats and dogs, weather phenomena, fireflies, and the night sky were certainly what got me interested in photography when I was a kid, anyhow.
Avoid the urge to incessantly demand that she constantly take and share pictures of people, especially family, as if this is some kind of obligation. Turning the hobby (or any hobby) into a chore will turn any kid off from it really quickly. Likewise, I think a much more important lesson than apertures and focal lengths and exposure times and math is the Ancient Knowledge: The path to good photography is in fact engaging in an awful lot of bad photography to get there. One should never be afraid to experiment, nor get discouraged if some -- or even most -- of their shots are not perfect. Especially shooting digital, when your film is infinite and free. Resist the urge to critique too much unless she asks for help on how to do better at taking a particular picture. Failure is okay, and you should probably also allow her to set the boundary (particularly at this age) that she can have private photos that others should not feel entitled to demand to see.
If she takes to it, then you can consider getting a cheap used DSLR body.
A prosumer point-and-shoot camera is a one time purchase and has the advantage of being totally self contained and incredibly versatile, but a DLSR/mirrorless can be an endless money pit of finding and throwing additional glass at it. It's probably best not to go down that rabbit hole until it seems justified.