From your post you have 10 days total, ever?? If so be proud your doing well. In addition you already made some great points that you know what your weak spots are. I was going to mention these.
This is all typical beginner riding, I did it, others did it and your doing it.
Since you know the knee thing I'll just generalize. Once you get those knees working you will be able to get those edges to initiate those turns. Instead of the skidded more flat based turns your doing. Nothing wrong with that, I did that for a long time, but once I learned to turn using the edges my riding jumped to the next level
Plus catching an edge from flat based turns hurts.
Keep at it, keep filming yourselves it is so much easier to evaluate your riding and pick out what needs work.
Have fun with it and it's great that you & your girl are doing this together