(https://www.amazon.com/Sock-Knitters-Handbook-Expert-Advice/dp/1604680466/ref=tmm_hrd_swatch_0?_encoding=UTF8&qid=&sr=)[The Sock Knitter's Handbook] gives various heels and toes (both toe-up and cuff-down) so you can choose whichever you want to try out different kinds of socks.
This book is what I use. You can even see on the last page of the preview of the book part of a chart. I've found it helpful for various sizes and I'm able to adjust for length if necessary.
You could do some sort of sock knitting kit? You can buy sock weight yarn at JoAnn Fabrics or even at a Local Yarn Store if you have one nearby. I'd do at least two balls of the yarn from Joann's, if that's the route you want to go. You could also include an easy beginner sock pattern like this one. She'll also need small double pointed needles, a US 1 or US 2. Like these. You could also get her this book! I just recently got the book, and it has a ton of tips and tricks that will help anyone interested in knitting socks! If you have any other questions, let me know and I'll try to answer them!