absolute beginner? Start at https://www.hedycode.com/

Which will ultimately lead into vanilla Python. This is the creator explaining why Hedy is uniquely designed for learning: https://www.youtube.com/watch?v=fmF7HpU_-9k

The official Python tutorial is very well written and is suitable for total beginners:

https://docs.python.org/3/tutorial/

These two are my favorite balance of fundamentals and getting to purposeful application as quickly as possible (the first link is definitely not enough, but combined with the second she should be comfortable with the syntax and able to get basic things working):
https://www.kaggle.com/learn/intro-to-programming
https://www.kaggle.com/learn/python

This one takes its time with fundamentals and includes some projects to put them in context of building something. It’s presented on Google Colab and Jupyter notebooks: https://allendowney.github.io/ThinkPython/

Working with GIS data means cleaning data. This one covers that and a lot of common analysis tools and techniques. But it assumes a bit of programming knowledge (Good to follow up after one of the options above: https://wesmckinney.com/book/

Automate the Boring Stuff with Python

Free to read on the authors website - https://automatetheboringstuff.com

Starting out with Python by Tony Graddis

I read the 3rd edition in library, now it’s 6th. Don’t know if it is as good as the memory serves.

She’s off to a great start! Most non-programmers starting off with python that I’ve seen are confused by the soaring and indexing rules, so can never get copy-pasted code to work

My older son always rebelled against programming, mostly because i thought he’d be great at it, but finally had to pick up some for a college class, I don’t know, stats or something. He became the programmer genius getting half the class to succeed, just because I drilled him on spacing and indenting

Second the Automate The Boring Stuff recommendation, especially if you’re looking for a physical gift (or free online as mentioned)

Id also just in general recommend CS50-python as a free course for python. Engaging lectures, problem sets you can check your solutions, and you finish with a project of your own choosing. No programming background is needed. Don’t buy a verified certificate, the whole course is free along with a free certificate

Get the basics locked.in before dipping into GIS.

Edit, because someone misunderstood me… You’ll have an easier time extending your existing GIS work by getting a nice foundation of non GIS python skills.

There’s a lot of odd patterns and domain specific requirements in the spatial data world, not even mentioning the nasty beast that esri is.

Provided you listen to my above advice, here are some other keywords that will help excite the home-gis dev: geopandas, (pandas), geojson, geopackage, QGIS, leaflet (not python but easy to connect a leaflet frontend with a python backend), openstreermaps, map box, earthexplorer (USGS free aerial imagery of lots of imagery types)

If it must be esri based, arcpy is a popular library.

I’d suggest SICP, but since you said Python:

https://wizardforcel.gitbooks.io/sicp-in-python/content/