I took a CPR class this year and highly recommend it for all. If there isn't a class nearby Red Cross has online versions of the class. Check their site. More people trained is more better

I think you did a great job! The most important thing is staying calm. This allowed you to think through stuff like not moving her head in case there was spinal damage.

Falls are so tough, you never know what causes them. Hip fractures (which this wasn't) come to mind. Lots of folks think they fall and break their hip where often, especially for elderly or those with low bone density the hip breaks and then you fall.

So did she faint or have a mini stroke or heart event or ... and then fall? That will be up to her doctor. But you stayed calm, made a note of her reactions which would have been important when EMT's arrive.

You done good!