Congratulations to your daughter!
The trouble with learning instruments is that it's not until you reach about grade 5 standard that you start to get much more fun out of playing. Until then there's a lot of hard slog, but you still can't play the pieces you would really like to, so it's easy to feel disheartened about practice.
I found what worked well for my son at about 12 was to tell him how much I enjoyed hearing him practise. He was quite amenable to playing whilst I prepared the dinner, which meant it was easy for me to give encouraging comments between scales, pieces, etc. I've never enjoyed cooking, so I could truthfully tell him that his playing brightened up a boring task for me, and this was a bit more incentive for him to practise.
At the end of the day, though, your daughter will decide for herself what she wants to spend her time doing, and if it isn't sax, you will have to accept that. Music lessons are never wasted, because the things your daughter has learned include listening, concentrating, acting on the teacher's instructions, etc, all of which are useful in school lessons too.
