Get her a lesson. You said that you only have about 20 days under your belt, that's not enough to begin trying to teach someone. Not by a long shot. That'll give you an hour or two on your own, and during which time she'll be learning better technique from an instructor so as to not spend the whole day on her ass and then hating you afterwards.
Then, remember to work with her after the lesson. Don't push too hard.
Damn I didn't see the 20 days part. Definitely get her a lesson, it is your only option at that skill level. You'll fail at teaching and she will fail at learning causing a big mess.
Trying to teach her yourself would be like giving tips to a scratch golfer as a 20 handicap, it just doesn't make sense.