I've just started the python learning journey. Combined with arduino. Current plan is for a homebrew true power meter.
One option I'm using for the learning stage is Raspbian desktop running on an emulator. (I'm using the virtual machine on my synology NAS, but it will also run in virtualbox.)
Raspbian is the default OS for the PI, and what you get is somthing that looks and feels almost exactly like the pi, but you can run it from your PC. There's even an emulator available for the GPIO (General purposes IO) available as a python library, so you'll be able to do pretty much everything your daughter can do on a physical PI.
If you do decide to get a physical PI, then the 3B+ is what you should go for. Simply not worth the few pounds saving for a lower spec version.